Lake surface temperature reconstruction method and device for regional climate simulation

Abstract

The application provides a lake surface temperature hourly reconstruction method and device for regional climate simulation, comprising determining a preset calendar window according to a target date to be reconstructed, and screening effective observation days according to data integrity; normalizing hourly measured water temperature of each effective observation day, and aggregating normalized values of the same hour to obtain a normalized intra-day temperature change reference sequence; obtaining satellite daytime lake surface temperature, satellite nighttime lake surface temperature and corresponding transit time of the target date, and mapping each transit time to a daytime anchor time and a nighttime anchor time; determining a vertical offset parameter and an intra-day amplitude scaling parameter according to the satellite daytime and nighttime lake surface temperature and the reference value of the reference sequence at the corresponding daytime and nighttime anchor time; and vertically offsetting and intra-day amplitude scaling the reference sequence according to the vertical offset parameter and the intra-day amplitude scaling parameter to generate an hourly lake surface temperature sequence of the target date.

Description

Technical Field

[0001] This invention relates to the field of regional climate simulation technology, and in particular to a method and apparatus for hourly reconstruction of lake surface temperature for regional climate simulation. Background Technology

[0002] Lake surface temperature is a crucial underlying surface state variable controlling the exchange of sensible heat, latent heat, and longwave radiation between the lake and the atmosphere. Its spatiotemporal variations can influence near-surface temperature and humidity, boundary layer structure, and local weather processes. Influenced by factors such as intra-lake circulation, wind mixing, and water depth distribution, the surface temperature of large lakes exhibits significant spatial heterogeneity, with substantial differences in temperature across different regions. Existing lake surface temperature data primarily originates from in-situ observations, lake physical models, and satellite thermal infrared remote sensing. In-situ observations provide high-temporal-resolution water temperature sequences, but typically only reflect the local water temperature at the sensor's location, making it difficult to characterize spatial differences in lake surface temperature. Lake physical models can continuously simulate lake surface temperature, but usually require parameters such as lake depth, water extinction coefficient, and initial water temperature profile. In lakes lacking long-term survey data, these parameters are difficult to obtain and calibrate accurately.

[0003] Compared to in-situ observations and lake physical models, satellite thermal infrared remote sensing can provide continuous spatial observations of lake surface temperature. However, due to limitations such as satellite orbit, transit frequency, and cloud cover, effective observations of the same lake can usually only be obtained for a limited number of moments during the day, such as daytime and nighttime, making it difficult to directly generate hourly lake surface temperature sequences. If the average daytime and nighttime temperature is directly used or a single satellite observation value is used as the lake surface temperature for the entire day, the intraday variation of the lake surface caused by solar heating and nighttime cooling will be ignored.

[0004] Existing technologies also employ methods that use pre-defined empirical curves, such as sine functions, to fit the intraday variations in lake surface temperature. However, the peak and trough times, as well as the temperature rise and fall processes, of these fixed empirical curves are typically determined by pre-defined function forms, making it difficult to adapt to the actual thermal cycle characteristics of different lakes and different seasons. Furthermore, directly determining the intraday temperature difference based solely on limited satellite observations may lead to abnormally amplified intraday amplitudes in the reconstructed sequence due to satellite observation errors or a small baseline temperature difference between day and night observation times. Summary of the Invention

[0005] This invention provides a method and apparatus for hourly reconstruction of lake surface temperature for regional climate simulation, which solves the shortcomings of existing technologies that use empirical curves such as sine functions to reconstruct intraday changes in lake surface temperature, which are difficult to effectively reflect the actual thermal cycle characteristics, and satellite observations are limited by the time of transit.

[0006] This invention provides a method for hourly reconstruction of lake surface temperature for regional climate simulation, comprising: determining a preset calendar window based on the target date to be reconstructed; obtaining hourly measured water temperatures of the target lake for each observation day within the preset calendar window over the years, and filtering valid observation days based on data integrity; normalizing the hourly measured water temperatures of each of the valid observation days, and aggregating the normalized values ​​for the same hour to obtain a normalized intraday temperature variation baseline sequence; obtaining the satellite daytime lake surface temperature, satellite nighttime lake surface temperature, and their corresponding transit times for the target date, and mapping each transit time to a daytime anchor time and a nighttime anchor time; determining a vertical offset parameter and an intraday amplitude scaling parameter based on the satellite daytime lake surface temperature, satellite nighttime lake surface temperature, and the baseline values ​​of the baseline sequence at the daytime and nighttime anchor times; and performing vertical offset and intraday amplitude scaling on the baseline sequence based on the vertical offset parameter and the intraday amplitude scaling parameter to generate an hourly lake surface temperature sequence for the target date.

[0007] According to the hourly lake surface temperature reconstruction method for regional climate simulation provided by the present invention, the determination of the vertical offset parameter and the intraday amplitude scaling parameter includes: determining candidate vertical offset parameters and candidate intraday amplitude scaling parameters based on the satellite daytime lake surface temperature, the satellite nighttime lake surface temperature, and the reference values ​​of the reference sequence at the daytime anchoring time and the nighttime anchoring time; transforming the reference sequence according to the candidate vertical offset parameters and the candidate intraday amplitude scaling parameters to obtain candidate hourly lake surface temperature sequences, and determining candidate intraday amplitudes based on the difference between the highest and lowest temperatures of the candidate hourly lake surface temperature sequences; comparing the candidate intraday amplitudes with a preset intraday amplitude threshold, and determining the vertical offset parameters and the intraday amplitude scaling parameters based on the comparison result.

[0008] According to the hourly reconstruction method for lake surface temperature for regional climate simulation provided by the present invention, the step of determining the vertical offset parameter and the intraday amplitude scaling parameter based on the comparison result includes: when the candidate intraday amplitude is less than or equal to the preset intraday amplitude threshold, determining the candidate vertical offset parameter and the candidate intraday amplitude scaling parameter as the vertical offset parameter and the intraday amplitude scaling parameter, respectively.

[0009] According to the hourly reconstruction method for lake surface temperature for regional climate simulation provided by the present invention, the step of determining the vertical offset parameter and the intraday amplitude scaling parameter based on the comparison result further includes: when the candidate intraday amplitude is greater than the preset intraday amplitude threshold, determining the reference intraday amplitude based on the difference between the maximum and minimum reference values ​​of the reference sequence; determining the intraday amplitude scaling ratio based on the preset intraday amplitude threshold and the reference intraday amplitude, and determining the intraday amplitude scaling parameter based on the sign of the candidate intraday amplitude scaling parameter and the intraday amplitude scaling ratio; determining the daytime offset based on the difference between the satellite daytime lake surface temperature and a first product, wherein the first product is the product of the intraday amplitude scaling parameter and the reference value of the reference sequence at the daytime anchoring time; determining the nighttime offset based on the difference between the satellite nighttime lake surface temperature and a second product, wherein the second product is the product of the intraday amplitude scaling parameter and the reference value of the reference sequence at the nighttime anchoring time; and performing an equal-weighted average of the daytime offset and the nighttime offset to obtain the vertical offset parameter.

[0010] According to the hourly lake surface temperature reconstruction method for regional climate simulation provided by the present invention, the generation of the hourly lake surface temperature sequence for the target date includes: identifying WRF lake grid points based on the land surface type variable in the WRF geostatic file, and determining the corresponding grid point spatial range based on the corner position information of each WRF lake grid point; assigning each satellite lake grid point to a corresponding WRF lake grid point based on the positional relationship between the satellite lake grid points and the spatial ranges of each grid point, and aggregating the satellite daytime lake surface temperature and satellite nighttime lake surface temperature corresponding to each WRF lake grid point to obtain the corresponding daytime anchor temperature and nighttime anchor temperature; for each WRF lake grid point, determining the grid point vertical offset parameter and the grid point intraday amplitude scaling parameter based on the corresponding daytime anchor temperature, nighttime anchor temperature and the reference sequence; and performing vertical offset and intraday amplitude scaling on the reference sequence based on the grid point vertical offset parameter and the grid point intraday amplitude scaling parameter to generate the hourly lake surface temperature sequence for each WRF lake grid point on the target date.

[0011] The hourly lake surface temperature reconstruction method for regional climate simulation provided by the present invention further includes: matching the hourly lake surface temperature of each WRF lake grid point with the WRF preprocessing intermediate file for the corresponding simulation time according to the target date and hour; reading the average surface temperature field of the WRF preprocessing intermediate file and constructing a lake grid mask based on the WRF lake grid points; writing the lake surface temperature for the corresponding simulation time into the lake grid points in the average surface temperature field according to the lake grid mask, while keeping the original temperature values ​​of non-lake grid points unchanged, to obtain an hourly lake surface temperature update file.

[0012] According to the method for hourly reconstruction of lake surface temperature for regional climate simulation provided by the present invention, the step of normalizing the hourly measured water temperature for each of the effective observation days and aggregating the normalized values ​​for the same hour to obtain a normalized intraday temperature change benchmark sequence includes: obtaining the minimum and maximum water temperatures for each of the effective observation days; normalizing the hourly measured water temperatures for the corresponding effective observation days based on the minimum and maximum water temperatures to obtain an hourly water temperature normalized sequence for each of the effective observation days; aggregating the hourly water temperature normalized sequences for each of the effective observation days and calculating the arithmetic mean of the normalized values ​​at the same hour to obtain a normalized intraday temperature change benchmark sequence.

[0013] This invention also provides an hourly lake surface temperature reconstruction device for regional climate simulation, comprising: a filtering module, used to determine a preset calendar window based on the target date to be reconstructed, obtain the hourly measured water temperature of the target lake for each observation day within the preset calendar window over the years, and filter valid observation days based on data integrity; a normalization module, used to normalize the hourly measured water temperature of each of the valid observation days respectively, and aggregate the normalized values ​​of the same hour to obtain a normalized intra-day temperature change baseline sequence; and an anchoring module, used to obtain the satellite daytime lake temperature for the target date. The system uses surface temperature, satellite nighttime lake surface temperature, and their corresponding transit times to map each transit time to a daytime anchor time and a nighttime anchor time. A parameter determination module determines vertical offset parameters and intraday amplitude scaling parameters based on the satellite daytime lake surface temperature, satellite nighttime lake surface temperature, and the baseline values ​​of the reference sequence at the daytime and nighttime anchor times. A reconstruction module performs vertical offset and intraday amplitude scaling on the reference sequence based on the vertical offset parameters and intraday amplitude scaling parameters to generate an hourly lake surface temperature sequence for the target date.

[0014] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the hourly reconstruction method for lake surface temperature for regional climate simulation as described above.

[0015] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the hourly reconstruction method for lake surface temperature for regional climate simulation as described above.

[0016] The present invention provides a method and apparatus for hourly reconstruction of lake surface temperature for regional climate simulation. Based on the target date to be reconstructed, a preset calendar window is determined from past dates. Valid observation days are selected from the preset calendar window, and then the hourly measured water temperatures for each valid observation day are normalized and aggregated according to the same hour. This weakens the differences in absolute temperature levels and intraday temperature variations between different observation days, thereby obtaining a normalized intraday temperature variation reference sequence that reflects the actual thermal cycle characteristics of the target lake. This avoids the drawback of fixed intraday variation curves such as preset sine functions failing to reflect actual trends. Based on this, the satellite daytime and nighttime lake surface temperatures for the target date are combined with the reference values ​​at the corresponding anchoring times to determine vertical offset parameters and intraday amplitude scaling parameters, so that the adjusted reference sequence reflects the absolute lake surface temperature level and diurnal temperature variation for the target date. Finally, the baseline sequence is transformed by vertical offset parameters and intraday amplitude scaling parameters. While preserving the typical intraday variation pattern of the target lake, the actual temperature level and diurnal variation information of the target date are introduced to generate a target date lake surface temperature sequence with hourly variation characteristics. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A flowchart of a method for hourly reconstruction of lake surface temperature for regional climate simulation is shown; Figure 2 The flowchart illustrates an example of the present invention, which normalizes the hourly measured water temperature for each valid observation day and aggregates the normalized values ​​for the same hour to obtain a normalized intra-day temperature change baseline sequence. Figure 3 This invention illustrates a graph consisting of an effective observation day normalized curve and a normalized intraday temperature change baseline sequence, representing an example of the present invention. Figure 4 A schematic diagram illustrating an example of determining the vertical offset parameter and intraday amplitude scaling parameter according to the present invention is shown. Figure 5 A graph showing the reconstructed lake surface temperature versus the intraday temperature variation baseline temperature is shown as an example of the present invention. Figure 6 A graph showing the satellite day-night observation anchor points and hourly reconstructed lake surface temperature curves for the target date; Figure 7Reconstruct the hourly spatial distribution map of lake surface temperature for the target date, grid-by-grid. Figure 8 A structural block diagram of the hourly reconstruction device for lake surface temperature for regional climate simulation of the present invention is shown. Figure 9 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] An embodiment of the present invention provides a method for hourly reconstruction of lake surface temperature for regional climate simulation.

[0021] Figure 1 A flowchart is shown for a method of hourly reconstructing lake surface temperature for regional climate simulation.

[0022] like Figure 1 As shown, the method includes operations S110~S150.

[0023] In operation S110, a preset calendar window is determined based on the target date to be reconstructed, the hourly measured water temperature of the target lake for each observation day within the preset calendar window over the years is obtained, and valid observation days are filtered based on data integrity.

[0024] According to an embodiment of the present invention, a preset calendar window can be determined based on the target date to be reconstructed, according to the calendar date or the cumulative day of the year, to represent the seasonal time range adjacent to the target date. When the target date is constructed according to a certain calendar distance, and there are preset calendar windows that span different years, the preset calendar window is determined according to the annual cycle.

[0025] After determining the preset calendar window, observation days that fall within the preset calendar window and meet the data integrity requirements are selected from all historical observation years to form a sample set of valid observation days. In some examples, the sample set of valid observation days does not require the historical observation year to be the same as the year of the target date, and no additional weights are set for different years.

[0026] For example, the preset calendar window includes seven calendar days before the target date, the target date itself, and seven calendar days after the target date, for a total of fifteen calendar days. Among these calendar days, days with at least 20 hours of valid water temperature data are selected as valid observation days.

[0027] In operation S120, the hourly measured water temperature for each valid observation day is normalized, and the normalized values ​​for the same hour are aggregated to obtain a normalized intra-day temperature change baseline sequence.

[0028] According to an embodiment of the present invention, since the overall temperature level and intraday temperature variation may differ across different historical observation days, directly aggregating hourly measured water temperatures would easily result in results influenced by individual high-temperature days, low-temperature days, or observation days with large intraday temperature differences. Therefore, each valid observation day can be used as a processing unit, mapping the hourly measured water temperatures of that valid observation day to a uniform numerical scale. In this way, the normalized hourly data can better characterize the relative high and low relationships and temperature rise and fall processes of water temperatures within each hour of that observation day.

[0029] Subsequently, the normalized water temperature results for each valid observation day were aggregated according to hourly location to obtain the baseline value for each hour, thus forming a normalized intraday temperature change baseline sequence. This approach weakens the influence of absolute temperature background and intraday temperature differences between different observation days while preserving the relatively stable intraday warming, cooling, and timing of high and low temperatures in the target lake within the seasonal range around the target date. This provides a basis for reconstructing the corresponding temperature change trend based on subsequent lake surface temperature obtained from satellite observations.

[0030] In operation S130, the daytime lake surface temperature and nighttime lake surface temperature of the satellite for the target date are obtained, along with their corresponding transit times. Each transit time is then mapped to a daytime anchoring time and a nighttime anchoring time.

[0031] According to an embodiment of the present invention, satellite monitoring data of the target lake surface temperature on the target date can be directly obtained. The monitoring data includes the lake surface temperature detected by the satellite during the daytime, i.e., the satellite daytime lake surface temperature, and the lake surface temperature detected by the satellite at nighttime, i.e., the satellite nighttime lake surface temperature, as well as the transit time corresponding to the obtained satellite daytime lake surface temperature and satellite nighttime lake surface temperature.

[0032] According to an embodiment of the present invention, the transit time can be mapped to the hour closest to the transit time, so as to serve as the daytime anchor time and the nighttime anchor time, respectively.

[0033] For example, suppose the satellite daytime lake surface temperature on the target date is... The corresponding transit time is The satellite image shows the lake surface temperature at night. The corresponding transit time is Map the transit time to the nearest whole hour:

[0034]

[0035] In operation S140, the vertical offset parameters and intraday amplitude scaling parameters are determined based on the satellite daytime lake surface temperature, the satellite nighttime lake surface temperature, and the reference values ​​of the reference sequence at the daytime and nighttime anchoring times.

[0036] According to an embodiment of the present invention, in order to convert a reference sequence into an actual lake surface temperature sequence for a target date, a transformation relationship between the reference value and the reconstructed lake surface temperature can be established. The vertical offset parameter is used to adjust the overall temperature level corresponding to the reference sequence, and the intraday amplitude scaling parameter is used to adjust the variation amplitude between high and low values ​​in the reference sequence. The reference values ​​of the reference sequence at the daytime anchoring time and the nighttime anchoring time are respectively linked to the corresponding satellite daytime lake surface temperature and satellite nighttime lake surface temperature. The vertical offset parameter and the intraday amplitude scaling parameter are then solved based on these constraints, enabling the reference sequence to reflect the actual lake surface temperature level and diurnal temperature variation for the target date.

[0037] According to an embodiment of the present invention, the reconstructed lake surface temperature for each hour of a target date can be represented by an affine transformation:

[0038] in, Indicates the target date The lake surface temperature was restored within hours. For the reference sequence in the 1st The baseline value for the hour. This is the vertical offset parameter. This is the intraday amplitude scaling parameter.

[0039] By substituting the daytime and nighttime anchoring times into the affine transformation relationship described above, the vertical offset parameter and the intraday amplitude scaling parameter can be solved, providing a basis for subsequent lake surface reconstruction.

[0040] In operation S150, the reference sequence is vertically offset and intraday amplitude scaled according to the vertical offset parameter and the intraday amplitude scaling parameter to generate the hourly lake surface temperature sequence for the target date.

[0041] According to an embodiment of the present invention, after obtaining the vertical offset parameter and the intraday amplitude scaling parameter, the reference values ​​of the reference sequence for each hour of the target date can be obtained sequentially. The reference values ​​for each hour are multiplied by the intraday amplitude scaling parameter to adjust the temperature change amplitude of the reference sequence during the day. The vertical offset parameter is then superimposed on the scaling result to adjust the absolute temperature level of the lake surface temperature for each hour, thereby obtaining the reconstructed lake surface temperature corresponding to each hour of the target date.

[0042] In one example, the WRF lake grid points covering the target lake can be determined based on WRF geostatic data, and the satellite daytime lake surface temperature and satellite nighttime lake surface temperature can be matched to the corresponding WRF lake grid points according to their spatial locations. For each WRF lake grid point, based on the vertical offset parameters and intraday amplitude scaling parameters determined in previous operations, the baseline values ​​for each hour in the baseline sequence are sequentially subjected to intraday amplitude scaling and vertical offset to obtain the reconstructed lake surface temperature for each hour on the target date for that WRF lake grid point. The above processing is performed on all WRF lake grid points covering the target lake to obtain the hourly lake surface temperature sequence for the target date.

[0043] Figure 2 The flowchart illustrates an example of the present invention, which normalizes the hourly measured water temperature for each valid observation day and aggregates the normalized values ​​for the same hour to obtain a normalized intra-day temperature change baseline sequence. Figure 3 The diagram illustrates an example of the present invention, showing a normalized curve of the effective observation day and a curve composed of a normalized intraday temperature change baseline sequence, wherein the black dashed line represents the curve composed of the normalized intraday temperature change baseline sequence.

[0044] like Figure 2 As shown, operation S120 includes operations S210~S230.

[0045] During operation S210, the minimum and maximum water temperatures for each valid observation day are obtained.

[0046] According to an embodiment of the present invention, the target date is set as The preset calendar window corresponding to the target date contains a total of One valid historical observation day. The first effective observation day The measured water temperature per hour was ,in .

[0047] Regarding the first For each valid observation day, the corresponding minimum and maximum water temperatures can be obtained:

[0048]

[0049] in, For the first The lowest water temperature on the effective observation day, For the first The highest water temperature on the effective observation day; For the first The first effective observation day The lake water temperature after one hour.

[0050] When operating S220, the hourly measured water temperature of the corresponding valid observation days is normalized according to the minimum and maximum water temperatures to obtain the hourly normalized water temperature sequence for each valid observation day.

[0051] For example, it is possible to [do something] on the [number]th Hourly measured water temperatures for each valid observation day were normalized to their minimum and maximum values:

[0052] in, For the first The first effective observation day Normalized water temperature per hour.

[0053] The above normalization operation is performed on each valid observation day to obtain the hourly normalized water temperature sequence for each valid observation day.

[0054] In operation S230, the hourly normalized water temperature sequences of each valid observation day are aggregated, and the arithmetic mean of the normalized values ​​at the same hour position is calculated to obtain the normalized intra-day temperature change baseline sequence.

[0055] According to an embodiment of the present invention, after minimum-maximum normalization, the lowest value of each valid observation day is mapped to 0, and the highest value is mapped to 1.

[0056] Furthermore, the hourly normalized water temperature sequences for each valid observation day are aggregated, and the normalized water temperature values ​​at the same hour are arithmetically averaged to obtain a normalized temperature baseline that can be used to reconstruct the target date.

[0057] in, For the target date The baseline value for the hour. The number of days of effective observation.

[0058] It can be seen that this temperature baseline does not carry historical absolute temperatures, but only characterizes the typical intraday variation pattern around the target date. The times of peak and trough values ​​in the baseline reflect the typical thermal cycle characteristics of the target lake in that season, and the number of effective observation days. The larger the value, the better the benchmark performs in averaging random noise, and the more stable the shape.

[0059] By solving the baseline values ​​of temperature changes for each hour of the day, a normalized baseline sequence of intraday temperature changes was obtained.

[0060] Figure 4 A schematic diagram illustrating an example of determining the vertical offset parameter and intraday amplitude scaling parameter according to the present invention is shown.

[0061] like Figure 4 As shown, operation S140 includes operations S410 to S430.

[0062] In operation S410, candidate vertical offset parameters and candidate intra-day amplitude scaling parameters are determined based on the satellite daytime lake surface temperature, the satellite nighttime lake surface temperature, and the reference values ​​of the reference sequence at the daytime and nighttime anchoring times.

[0063] According to an embodiment of the present invention, the daytime anchoring time and the nighttime anchoring time can be substituted into the above-described affine transformation relationship, and the daytime lake surface temperature and the nighttime lake surface temperature can be used as the temperature constraints for the corresponding times, as follows:

[0064]

[0065] in, This indicates the daytime lake surface temperature indicated by the satellite. The satellite indicates the nighttime lake surface temperature. Indicates the daytime anchoring time. Indicates the nighttime anchoring time. Indicates the candidate vertical offset parameter. Indicates the candidate intraday amplitude scaling parameter. Indicates the reference sequence at the 1st The baseline value for the hour.

[0066] By solving the above constraints, candidate vertical offset parameters and candidate intraday amplitude scaling parameters can be obtained, namely:

[0067]

[0068] In operation S420, the reference sequence is transformed according to the candidate vertical offset parameter and the candidate intra-day amplitude scaling parameter to obtain the candidate hourly lake surface temperature sequence, and the candidate intra-day amplitude is determined according to the difference between the highest and lowest temperatures of the candidate hourly lake surface temperature sequence.

[0069] For example, candidate intraday amplitudes can be obtained in the following ways:

[0070] in, For candidate intraday amplitude, The highest temperature in the candidate hourly lake surface temperature series. The lowest temperature in the candidate hourly lake surface temperature series.

[0071] In operation S430, the candidate intraday amplitude is compared with the preset intraday amplitude threshold, and the vertical offset parameter and intraday amplitude scaling parameter are determined based on the comparison result.

[0072] According to an embodiment of the present invention, since the candidate intraday amplitude directly determined based on the daytime anchor temperature and the nighttime anchor temperature may be affected by the satellite observation time interval, observation error, and abnormal changes in daytime and nighttime temperature differences, causing the intraday temperature change range of the candidate reconstruction sequence to deviate from the actual change range of the target lake, a preset intraday amplitude threshold is set. By setting the preset intraday amplitude threshold, it is possible to determine whether and how to adjust the candidate vertical offset parameter and the candidate intraday amplitude scaling parameter. Thus, the vertical offset parameter and the intraday amplitude scaling parameter can be determined.

[0073] In one illustrative embodiment, if the candidate intra-day amplitude is less than or equal to a preset intra-day amplitude threshold, it indicates that the intra-day variation range of the candidate hourly lake surface temperature sequence corresponding to the candidate parameters determined based on the satellite daytime and nighttime lake surface temperatures is within a preset reasonable range. Therefore, it can be considered that the candidate vertical offset parameter and the candidate intra-day amplitude scaling parameter simultaneously satisfy the target date satellite observation constraint and the intra-day variation range constraint, and the candidate vertical offset parameter is directly determined as the vertical offset parameter, and the candidate intra-day amplitude scaling parameter is determined as the intra-day amplitude scaling parameter.

[0074] In one illustrative embodiment, if the intraday amplitude of a candidate is greater than a preset intraday amplitude threshold, it indicates that the intraday variation does not meet the preset reasonable range. Therefore, it is necessary to adjust the candidate vertical offset parameter and the candidate intraday amplitude scaling parameter. The specific operation is as follows: The intraday amplitude is determined based on the difference between the maximum and minimum benchmark values ​​of the benchmark sequence:

[0075] in, The intraday amplitude is the baseline. The maximum benchmark value of the benchmark sequence. It is the minimum benchmark value of the benchmark sequence.

[0076] The intraday amplitude scaling ratio is determined based on the preset intraday amplitude threshold and the baseline intraday amplitude, and the intraday amplitude scaling parameter is determined based on the positive or negative sign of the candidate intraday amplitude scaling parameter and the intraday amplitude scaling ratio.

[0077] Specifically, the intraday amplitude scaling parameter can be determined by the following formula:

[0078] in, This is the intraday amplitude scaling parameter. This represents a sign function, which takes the value 1 when the input value is greater than 0 and -1 when the input value is less than 0.

[0079] The daytime offset is determined based on the difference between the satellite's daytime lake surface temperature and the first product, where the first product is the product of the intraday amplitude scaling parameter and the reference value of the reference sequence at the daytime anchoring time.

[0080] Specifically, the daytime offset can be expressed as: .

[0081] The nighttime offset is determined by the difference between the satellite's nighttime lake surface temperature and the second product, where the second product is the product of the intraday amplitude scaling parameter and the reference value of the reference sequence at the nighttime anchoring time.

[0082] Specifically, the nighttime offset can be expressed as:

[0083] The vertical offset parameter is obtained by performing an equal-weighted average of the daytime and nighttime offsets.

[0084] According to an embodiment of the present invention, the vertical offset parameter It can be represented as:

[0085] Therefore, the intraday amplitude scaling can retain the scaling direction corresponding to the diurnal temperature difference of the satellite, and the reconstructed curve can be as close as possible to the diurnal satellite observations, provided that the intraday amplitude does not exceed the preset threshold.

[0086] It should be noted that in determining the intraday amplitude scaling parameters and vertical offset parameters, different target dates are independently reconstructed based on their corresponding intraday variation benchmarks and the daytime and nighttime satellite observations of that day, without cross-day smoothing.

[0087] In one illustrative embodiment, the process of generating an hourly sequence of lake surface temperatures for a target date includes: Identify WRF lake grid points based on the land surface type variable in the WRF geostatic file, and determine the corresponding grid point spatial range based on the corner location information of each WRF lake grid point.

[0088] According to an embodiment of the present invention, the land surface type variable in the WRF geographic static file can be read, the WRF lake grid points can be identified according to the preset lake land surface type code, the latitude and longitude of the corner points of each WRF lake grid point can be read, and the grid point spatial polygon can be constructed based on the four corner points.

[0089] Based on the positional relationship between the satellite lake grid points and the spatial range of each grid point, each satellite lake grid point is assigned to the corresponding WRF lake grid point. The satellite daytime lake surface temperature and satellite nighttime lake surface temperature corresponding to each WRF lake grid point are then aggregated to obtain the corresponding daytime anchor temperature and nighttime anchor temperature.

[0090] Specifically, WRF lake grid points are set. The corresponding spatial polygon is Satellite lake grid The central position is A grid set of satellite lake points is established by determining whether a point lies within a polygon. :

[0091] For each set The WRF lake grid is obtained by averaging the daytime and nighttime lake surface temperatures of the inner satellite lake grid. Daytime anchoring temperature and nighttime anchoring temperature :

[0092]

[0093] For each WRF lake grid point, the grid point vertical offset parameter and the grid point intraday amplitude scaling parameter are determined based on the corresponding daytime anchor temperature, nighttime anchor temperature and reference sequence.

[0094] Based on the grid vertical offset parameters and the grid intra-day amplitude scaling parameters, the baseline sequence is vertically offset and intra-day amplitude scaling is performed to generate the hourly lake surface temperature sequence for each WRF lake grid point on the target date.

[0095] According to an embodiment of the present invention, for each WRF lake grid point, respectively and Substituting the aforementioned calculation relationship between intraday amplitude scaling parameters and vertical offset parameters, we obtain the vertical offset parameters corresponding to the grid points. Intraday amplitude scaling parameters And generate hourly lake surface temperatures that vary at spatially defined grid points:

[0096] In one example, when a WRF lake grid point has no corresponding satellite lake grid point or the corresponding data is invalid, it is first filled by the average value of the valid lake grid points in its eight neighborhoods; when there are no valid lake grid points in the neighborhood, the latitude and elevation are normalized, and the valid lake grid point with the smallest latitude-elevation two-dimensional distance is selected as the replacement grid point.

[0097] In one illustrative embodiment, the hourly reconstruction method for lake surface temperature for regional climate simulation of the present invention further includes: Based on the target date and hour, the hourly lake surface temperature of each WRF lake grid point is matched with the WRF preprocessing intermediate file for the corresponding simulation time.

[0098] According to an embodiment of the present invention, during regional climate simulation, the WRF model typically generates corresponding preprocessing intermediate files according to preset simulation times, with different simulation times corresponding to different time nodes of the model input state. To ensure that the reconstructed hourly lake surface temperature is consistent with the time information during the WRF model simulation, the corresponding simulation time is determined based on the target date and target hour, and the WRF preprocessing intermediate file corresponding to the simulation time is read. Further, based on the time information corresponding to the WRF lake grid points, the hourly lake surface temperature corresponding to each WRF lake grid point on the target date and target hour is matched with the WRF preprocessing intermediate file to determine the lake surface temperature data to be updated.

[0099] Read the average surface temperature field from the WRF preprocessing intermediate file and construct a lake grid mask based on the WRF lake grid.

[0100] According to embodiments of the present invention, the average surface temperature field in the WRF preprocessing intermediate file can be read. This field stores surface temperature information corresponding to each grid point within the WRF model calculation area. Based on the location distribution of the WRF lake grid points, a lake grid mask is constructed to characterize the location of the lake region. This mask distinguishes between lake and non-lake grid points in the average surface temperature field. Using the lake grid mask, the locations of grid points in the average surface temperature field that need to be updated using the reconstructed lake surface temperature can be determined.

[0101] In one example, based on the target date and hours Positioning and The corresponding hourly preprocessing intermediate file is used, and the average surface temperature field in the file is read. A lake grid mask with the same dimensions as the WRF horizontal grid is then constructed. When grid points When the grid is for lakes, ;otherwise, .

[0102] No. The hourly average surface temperature is:

[0103] in, To update the average surface temperature field at the grid points The value, The updated values ​​are shown below. The selective update relationship described above replaces the lake grid points with the reconstructed lake surface temperature for the corresponding hour, while non-lake grid points retain their original values.

[0104] Based on the lake grid mask, the lake surface temperature corresponding to the simulation time is written into the lake grid in the average surface temperature field, while keeping the original temperature values ​​of non-lake grid points unchanged, thus obtaining the hourly lake surface temperature update file.

[0105] According to an embodiment of the present invention, the lake grid locations in the average surface temperature field are determined based on a lake grid mask, and the hourly lake surface temperature corresponding to the current simulation time is written into the corresponding lake grid to replace the temperature value at the corresponding location in the original average surface temperature field. For locations in the lake grid mask not identified as lake grids, the original temperature value in the average surface temperature field is retained unchanged. After the lake grid temperature update is completed, an hourly lake surface temperature update file for the corresponding simulation time is generated.

[0106] The following describes the hourly reconstruction device for lake surface temperature in regional climate simulation provided by the present invention. The hourly reconstruction device for lake surface temperature in regional climate simulation described below can be referred to in correspondence with the hourly reconstruction method for lake surface temperature in regional climate simulation described above.

[0107] Figure 8 A structural block diagram of the hourly lake surface temperature reconstruction device for regional climate simulation of the present invention is shown.

[0108] like Figure 8 As shown, the hourly lake surface temperature reconstruction device 800 for regional climate simulation includes a screening module 810, a normalization module 820, an anchoring module 830, a parameter determination module 840, and a reconstruction module 850.

[0109] The filtering module 810 is used to determine the preset calendar window based on the target date to be reconstructed, obtain the hourly measured water temperature of the target lake for each observation day within the preset calendar window over the years, and filter the valid observation days based on data integrity.

[0110] The normalization module 820 is used to normalize the hourly measured water temperature for each valid observation day, and to aggregate the normalized values ​​for the same hour to obtain a normalized intra-day temperature change baseline sequence.

[0111] The anchoring module 830 is used to obtain the satellite daytime lake surface temperature, the satellite nighttime lake surface temperature and the corresponding transit time for the target date, and to map each transit time to a daytime anchoring time and a nighttime anchoring time.

[0112] The parameter determination module 840 is used to determine the vertical offset parameter and the intraday amplitude scaling parameter based on the satellite daytime lake surface temperature, the satellite nighttime lake surface temperature, and the reference values ​​of the reference sequence at the daytime anchoring time and the nighttime anchoring time.

[0113] The reconstruction module 850 is used to perform vertical offset and intraday amplitude scaling on the reference sequence based on the vertical offset parameter and the intraday amplitude scaling parameter to generate an hourly lake surface temperature sequence for the target date.

[0114] Figure 9 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 9 As shown, the electronic device may include a processor 910, a communications interface 920, a memory 930, and a communication bus 940. The processor 910, communications interface 920, and memory 930 communicate with each other via the communication bus 940. The processor 910 can call logical instructions from the memory 930 to execute a method for hourly reconstruction of lake surface temperature for regional climate simulation.

[0115] Furthermore, the logical instructions in the aforementioned memory 930 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0116] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer is able to execute the hourly reconstruction method for lake surface temperature for regional climate simulation provided by the above methods.

[0117] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the hourly reconstruction method for lake surface temperature for regional climate simulation provided by the methods described above.

[0118] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0119] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for hourly reconstruction of lake surface temperature for regional climate simulation, characterized in that, include: The preset calendar window is determined based on the target date to be reconstructed. The hourly measured water temperature of the target lake for each observation day within the preset calendar window over the years is obtained, and the valid observation days are filtered according to the data integrity. The hourly measured water temperature for each of the effective observation days was normalized, and the normalized values ​​for the same hour were aggregated to obtain a normalized intra-day temperature change baseline sequence. Obtain the daytime and nighttime lake surface temperatures from the satellite for the target date, along with their corresponding transit times, and map each transit time to a daytime anchoring time and a nighttime anchoring time. Based on the daytime lake surface temperature, nighttime lake surface temperature, and the reference values ​​of the reference sequence at the daytime and nighttime anchoring times, determine the vertical offset parameter and the intraday amplitude scaling parameter; Based on the vertical offset parameter and the intraday amplitude scaling parameter, the reference sequence is vertically offset and intraday amplitude scaling is performed to generate the hourly lake surface temperature sequence for the target date.

2. The method for hourly reconstruction of lake surface temperature for regional climate simulation according to claim 1, characterized in that, The determination of the vertical offset parameter and the intraday amplitude scaling parameter includes: Based on the daytime lake surface temperature of the satellite, the nighttime lake surface temperature of the satellite, and the reference values ​​of the reference sequence at the daytime anchoring time and the nighttime anchoring time, candidate vertical offset parameters and candidate intra-day amplitude scaling parameters are determined; The reference sequence is transformed according to the candidate vertical offset parameter and the candidate intra-day amplitude scaling parameter to obtain the candidate hourly lake surface temperature sequence, and the candidate intra-day amplitude is determined according to the difference between the highest and lowest temperatures of the candidate hourly lake surface temperature sequence. The candidate intraday amplitude is compared with a preset intraday amplitude threshold, and the vertical offset parameter and the intraday amplitude scaling parameter are determined based on the comparison result.

3. The method for hourly reconstruction of lake surface temperature for regional climate simulation according to claim 2, characterized in that, The step of determining the vertical offset parameter and the intraday amplitude scaling parameter based on the comparison results includes: When the intra-day amplitude of the candidate is less than or equal to the preset intra-day amplitude threshold, the candidate vertical offset parameter and the candidate intra-day amplitude scaling parameter are respectively determined as the vertical offset parameter and the intra-day amplitude scaling parameter.

4. The method for hourly reconstruction of lake surface temperature for regional climate simulation according to claim 2, characterized in that, The step of determining the vertical offset parameter and the intraday amplitude scaling parameter based on the comparison result further includes: If the amplitude within the candidate day is greater than the preset intraday amplitude threshold, the intraday amplitude of the reference day is determined based on the difference between the maximum and minimum reference values ​​of the reference sequence. The intraday amplitude scaling ratio is determined based on the preset intraday amplitude threshold and the baseline intraday amplitude, and the intraday amplitude scaling parameter is determined based on the sign of the candidate intraday amplitude scaling parameter and the intraday amplitude scaling ratio. The daytime offset is determined based on the difference between the daytime lake surface temperature of the satellite and the first product, wherein the first product is the product of the intraday amplitude scaling parameter and the reference value of the reference sequence at the daytime anchoring time; The nighttime offset is determined based on the difference between the satellite's nighttime lake surface temperature and the second product, wherein the second product is the product of the intraday amplitude scaling parameter and the reference value of the reference sequence at the nighttime anchoring time; The vertical offset parameter is obtained by performing an equal-weighted average of the daytime offset and the nighttime offset.

5. The method for hourly reconstruction of lake surface temperature for regional climate simulation according to claim 1, characterized in that, The generation of the hourly lake surface temperature sequence for the target date includes: Identify WRF lake grid points based on the land surface type variables in the WRF geographic static file, and determine the corresponding grid point spatial range based on the corner position information of each WRF lake grid point; Based on the positional relationship between the satellite lake grid points and the spatial range of each grid point, each satellite lake grid point is assigned to the corresponding WRF lake grid point, and the satellite daytime lake surface temperature and satellite nighttime lake surface temperature corresponding to each WRF lake grid point are aggregated to obtain the corresponding daytime anchor temperature and nighttime anchor temperature. For each WRF lake grid point, the grid point vertical offset parameter and the grid point intraday amplitude scaling parameter are determined based on the corresponding daytime anchor temperature, nighttime anchor temperature and the reference sequence. Based on the grid point vertical offset parameter and the grid point intra-day amplitude scaling parameter, the reference sequence is vertically offset and intra-day amplitude scaling is performed to generate the hourly lake surface temperature sequence for each WRF lake grid point on the target date.

6. The method for hourly reconstruction of lake surface temperature for regional climate simulation according to claim 5, characterized in that, Also includes: Based on the target date and hour, the hourly lake surface temperature of each WRF lake grid point is matched with the WRF preprocessing intermediate file for the corresponding simulation time. Read the average surface temperature field from the WRF preprocessing intermediate file and construct a lake grid mask based on the WRF lake grid. Based on the lake grid mask, the lake surface temperature corresponding to the simulation time is written into the lake grid in the average surface temperature field, while keeping the original temperature values ​​of non-lake grids unchanged, to obtain an hourly lake surface temperature update file.

7. The method for hourly reconstruction of lake surface temperature for regional climate simulation according to claim 1, characterized in that, The method involves normalizing the hourly measured water temperature for each of the effective observation days, and aggregating the normalized values ​​for the same hour to obtain a normalized intra-day temperature change baseline sequence, including: Obtain the minimum and maximum water temperatures for each of the effective observation days; Based on the minimum and maximum water temperatures, the hourly measured water temperatures for the corresponding valid observation days are normalized to obtain the hourly water temperature normalization sequence for each valid observation day. The hourly normalized water temperature sequences for each of the effective observation days are aggregated, and the arithmetic mean of the normalized values ​​at the same hour position is calculated to obtain the normalized intra-day temperature change baseline sequence.

8. A time-by-time reconstruction device for lake surface temperature for regional climate simulation, characterized in that, include: The filtering module is used to determine a preset calendar window based on the target date to be reconstructed, obtain the hourly measured water temperature of the target lake for each observation day within the preset calendar window over the years, and filter valid observation days based on data integrity. The normalization module is used to normalize the hourly measured water temperature for each of the effective observation days, and to aggregate the normalized values ​​for the same hour to obtain a normalized intra-day temperature change baseline sequence. An anchoring module is used to obtain the satellite daytime lake surface temperature, satellite nighttime lake surface temperature and corresponding transit times for the target date, and map each transit time to a daytime anchoring time and a nighttime anchoring time; The parameter determination module is used to determine the vertical offset parameter and the intraday amplitude scaling parameter based on the satellite daytime lake surface temperature, the satellite nighttime lake surface temperature, and the reference values ​​of the reference sequence at the daytime anchoring time and the nighttime anchoring time. The reconstruction module is used to perform vertical offset and intraday amplitude scaling on the reference sequence according to the vertical offset parameter and the intraday amplitude scaling parameter, so as to generate the hourly lake surface temperature sequence for the target date.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the hourly reconstruction method for lake surface temperature for regional climate simulation as described in any one of claims 1 to 7.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the hourly reconstruction method for lake surface temperature for regional climate simulation as described in any one of claims 1 to 7.

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