An outdoor sensible heat environment evaluation method considering both shading and sunshine scenarios

Abstract

The present application relates to the field of meteorological environment assessment, and more particularly to an outdoor thermal environment assessment method considering shadow and sunshine scenarios. The present application comprises: obtaining and preprocessing the basic environmental data of a target area and time matching; calculating the apparent temperature under the shadow condition by using the empirical apparent temperature model according to the shadow air temperature, relative humidity and wind speed; constructing the temperature representation under the direct sunshine scenario based on the shadow air temperature and the ground temperature; calculating the apparent temperature under the direct sunshine scenario by replacing the air temperature input item in the empirical apparent temperature model with the sunshine temperature; calculating the difference values of the sunshine apparent temperature, the shadow apparent temperature and the shadow air temperature respectively, and then outputting the outdoor thermal environment assessment results and their spatial distribution characteristics of the target area based on the calculation results. The present application solves the problems that the empirical apparent temperature index is difficult to reasonably represent the additional heat effect of direct sunshine, and the thermal comfort model has many input parameters, the index is difficult to obtain, and the calculation process is complex.

Description

Technical Field

[0001] This invention relates to the field of meteorological environment assessment, and more particularly to an outdoor perceived thermal environment assessment method that considers both shaded and sunny scenarios. Background Technology

[0002] In outdoor activities, urban public space use, tourism, and thermal health protection scenarios, the human body is often simultaneously affected by multiple factors such as temperature, humidity, wind speed, and solar radiation. Especially under clear skies or few clouds, solar radiation significantly increases the human body's thermal load, leading to a marked difference in perceived thermal environment between shaded and sunny conditions. With increasing attention being paid to outdoor heat exposure, how to rationally characterize the perceived temperature of the human body under different exposure conditions has become an important research topic in this field.

[0003] Existing methods for assessing outdoor perceived thermal environment mainly fall into two categories. One category constructs empirical perceived temperature indices based on conventional meteorological elements such as air temperature, relative humidity, and wind speed. Indicators like the Heat Index (HI) and Effective Temperature (ET) typically express the perceived temperature as a function of air temperature, humidity, and wind speed. This type of method requires fewer input parameters, has a wide range of data sources, and is relatively simple to calculate, making it suitable for regional scales and long-term series analysis. However, these methods generally primarily reflect the human thermal sensation under shaded or standard observation conditions and are difficult to directly characterize the additional radiative heat load borne by the human body under direct sunlight.

[0004] Another type of method further considers the effects of solar radiation, typically using thermal comfort indices such as the Universal Thermal Climate Index (UTCI) and Physiological Equivalent Temperature (PET) for assessment. This type of method usually requires the input of radiation parameters such as mean radiant temperature and black spherical temperature during calculation. Some methods also require the incorporation of anthropometric parameters such as clothing thermal resistance, metabolic rate, height, and weight, and are solved using thermal balance models or specialized models. For example, existing studies have required simultaneous input of air temperature, relative humidity, wind speed, and mean radiant temperature for UTCI calculations, with the mean radiant temperature often needing to be converted using black spherical temperature; similarly, PET calculations require input of multiple meteorological and anthropometric parameters. While this type of method can reflect the effects of solar radiation more comprehensively, it requires a large number of indicators, some parameters are difficult to obtain, and the calculation process is relatively complex.

[0005] Therefore, existing technologies have at least the following shortcomings: First, empirical methods based solely on air temperature, humidity, and wind speed are insufficient to reasonably characterize the enhanced thermal sensation effect on the human body under direct sunlight. Second, thermal comfort models considering solar radiation typically rely on hard-to-obtain indicators such as mean radiation temperature, black sphere temperature, or human body parameters, resulting in high application costs and making them difficult to directly apply to large-scale, long-term series and routine operational scenarios. Third, existing methods lack a technical solution for easily quantifying and uniformly calculating the additional thermal effects of direct sunlight while preserving the simplicity and operability of empirical models. Based on this, it is necessary to propose an improved method for calculating the perceived temperature under direct sunlight in outdoor thermal environment assessment, to achieve a simplified characterization of the impact of solar radiation based on conventional meteorological data. Summary of the Invention

[0006] This invention provides an outdoor perceived thermal environment assessment method that considers both shaded and sunny scenarios. It addresses the problem that existing outdoor perceived thermal environment assessment methods often fail to adequately characterize the additional heat effect of direct sunlight using empirical perceived temperature indices, while thermal comfort models that consider solar radiation suffer from numerous input parameters, difficulty in obtaining indices, and complex calculation processes.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An outdoor perceived thermal environment assessment method considering both shade and sunshine scenarios includes the following steps:

[0009] Step S1: Obtain basic environmental data for the target area, including at least shaded temperature. relative humidity Wind speed and surface temperature Furthermore, data preprocessing and time matching processing are performed on the basic environmental data to ensure the correspondence of each variable on a unified time scale.

[0010] Step S2: Based on the temperature in the shade relative humidity and wind speed An empirical perceived temperature model was used to calculate the perceived temperature under shaded conditions, and the shaded perceived temperature was obtained. ;

[0011] Step S3, based on shaded temperature and surface temperature To construct a temperature characterization quantity under direct sunlight scenario, namely solar radiation temperature. Among them, temperature index (sunlight temperature) An empirical index used to approximate the intensity of the external thermal environment under solar radiation conditions;

[0012] Step S4: Set the solar radiation temperature Instead of the air temperature input in the empirical perceived temperature model, the perceived temperature under direct sunlight is calculated to obtain the perceived temperature under sunshine conditions. ;

[0013] Step S5: Calculate the perceived temperature under sunlight. Shade-induced body temperature Shady temperature The difference , , ;

[0014] Step S6: Based on the perceived temperature under shade Sunlight perceived temperature The difference between the target area and the outdoor thermal environment assessment results and their spatial distribution characteristics are output.

[0015] Furthermore, in step S1, the basic environmental data can be derived from ground meteorological observation data, remote sensing inversion data, or fused data obtained by matching the two.

[0016] Furthermore, in step S1, the data preprocessing of the basic environmental data includes: missing value removal and outlier detection.

[0017] Furthermore, in step S2, the perceived temperature under shade... The following relationship must be satisfied:

[0018] (1)

[0019] in, The temperature (°C) is located 2 meters above the ground. Wind speed (m / s) This represents the actual water vapor pressure (hPa).

[0020] Furthermore, water vapor pressure According to the temperature in the shade and relative humidity Calculation is performed:

[0021] (2)

[0022] in, The relative humidity (%) is 2m above the ground.

[0023] Furthermore, in step S3, the solar radiation temperature The calculation method is as follows:

[0024] (3)

[0025] in, For surface temperature, Weighting coefficients for the contribution of surface warming to the external thermal environment under direct solar radiation scenarios.

[0026] Furthermore, weighting coefficients The range of values ​​is Preferably, .

[0027] Furthermore, in step S4, the perceived temperature under sunlight... The calculation method is as follows:

[0028] (4)

[0029] in, Wind speed (m / s) This represents the actual water vapor pressure (hPa).

[0030] Furthermore, in step S5, the specific calculation of each difference (i.e., scenario difference) is as follows:

[0031] (5)

[0032] (6)

[0033] (7)

[0034] in, Characterizes the additional thermal effect produced by direct sunlight conditions relative to shaded conditions. Characterizes the overall deviation of the actual heat load felt by the human body under sunlight conditions relative to the background shady temperature. It characterizes the degree of deviation between perceived temperature and actual air temperature under shaded conditions.

[0035] Furthermore, it also includes step S7: adjusting the perceived temperature under shade. Sunlight perceived temperature The time series of the difference between the time series and the time series are used for trend analysis and the output is visualized.

[0036] Furthermore, in step S7, linear trend analysis is used to characterize the slope of change, and the Mann-Kendall trend test is used to examine the significance of the change trend. Linear trend analysis characterizes the direction and magnitude of each indicator's change over time, while the Mann-Kendall trend test determines the significance of each indicator's change trend. Through linear trend analysis and the Mann-Kendall trend test, the long-term trends and differences in the perceived outdoor thermal environment across different regions, seasons, underlying surface types, or climate zones can be further identified.

[0037] In this invention, instead of characterizing the effects of solar radiation by introducing parameters such as average radiation temperature and black sphere temperature, the treatment of the additional heat effect of direct solar radiation is moved forward to the temperature characterization level, by constructing a comprehensive temperature characterization quantity under the scenario of direct solar radiation. Then, the solar radiation perceived temperature is calculated based on an empirical perceived temperature model. Thus, this invention transforms the calculation process, which originally required complex acquisition of radiation parameters and solution of thermal balance, into a temperature correction and formula substitution process, thereby reducing the number of input parameters, simplifying the calculation process, and reducing the computational burden in regional-scale and long-term series applications.

[0038] In this invention, the temperature characterization quantity under direct sunlight is... It is not the actual air temperature obtained by solving a complex human energy balance model, but a temperature variable that empirically represents the degree of enhancement of the external thermal environment under direct sunlight by introducing surface warming information on the basis of shaded air temperature.

[0039] This invention is preferably applicable to outdoor solar exposure scenarios under clear or partly cloudy daytime conditions. Under these conditions, the surface temperature is not lower than the shaded air temperature, and the surface warming signal can characterize the additional thermal effect of solar radiation. This method can also be used for different regions, seasons, underlying surface types, or climate zones. , Statistical analysis was conducted on various difference indicators to identify the spatiotemporal differences in the additional heat effect of direct solar radiation.

[0040] The technical solution provided by this invention brings at least the following beneficial effects:

[0041] (1) Based on the empirical somatic temperature model, this invention introduces surface warming information to construct a comprehensive temperature characterization quantity under direct sunlight scenario, thereby characterizing the additional heat effect caused by direct sunlight, which makes up for the shortcomings of existing empirical methods that are mainly applicable to shaded conditions and difficult to handle direct sunlight scenario.

[0042] (2) This invention does not require the introduction of complex input parameters such as average radiation temperature, black sphere temperature, human metabolic rate or clothing thermal resistance. Instead, it can complete the calculation of the perceived temperature under sunshine conditions using only shaded air temperature, relative humidity, wind speed and ground surface temperature, thereby reducing the difficulty of obtaining input parameters.

[0043] (3) This invention does not require complex human energy balance solutions. Instead, it constructs a comprehensive temperature characterization quantity under direct sunlight and substitutes it into an empirical somatic temperature formula for calculation. This simplifies the characterization of the influence of direct sunlight into a temperature correction and formula substitution process, reducing the calculation steps and lowering the computational burden in large-scale, long-term applications.

[0044] (4) By calculating the shaded temperature, the sunshine temperature and their difference, the background thermal environment characteristics and the additional heat effect caused by direct sunlight can be reflected at the same time.

[0045] (5) Compared with existing empirical ergonomic temperature methods that are only applicable to shaded conditions, this invention can characterize the additional thermal effects under direct sunlight. Compared with complex thermal comfort models that rely on mean radiation temperature, black sphere temperature and human body thermal balance parameters, this invention has fewer input parameters, shorter calculation process and more convenient data acquisition. Therefore, while maintaining the operability of the method, it reduces the computational complexity and is more suitable for regional scale ergonomic thermal environment assessment.

[0046] (6) The method is simple, operable and applicable at the regional scale, and can be used for outdoor thermal environment assessment, thermal risk identification and spatiotemporal variation analysis under large-scale and long-term time series conditions. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 The flowchart of the method of the present invention shows the overall process of acquiring basic environmental data, calculating shaded perceived temperature, constructing a comprehensive temperature characterization quantity for direct sunlight, calculating sunshine perceived temperature, and outputting the difference index.

[0049] Figure 2 The core calculation relationship diagram of the method of the present invention shows the correspondence between shaded air temperature, relative humidity, wind speed and surface temperature and shaded perceived temperature, sunshine perceived temperature and various difference indicators;

[0050] Figure 3 This is a spatial distribution diagram of shaded temperature, shaded perceived temperature, and sunshine perceived temperature obtained by the method of the present invention.

[0051] Figure 4 This is a graph showing the time-varying results of shaded temperature, shaded perceived temperature, sunshine perceived temperature, and the difference index obtained by the method of the present invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be described in detail and completely below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Generally, the components of the embodiments of the present invention described and shown in the accompanying drawings can be arranged and designed using different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the present invention.

[0053] To address the shortcomings of existing methods for assessing outdoor perceived thermal environment, such as the difficulty in accurately representing the additional heat effect of direct sunlight with empirically-based perceived temperature indices, and the challenges of complex calculation processes with thermal comfort models that consider solar radiation, this invention provides a method for assessing outdoor perceived thermal environment that considers both shaded and sunny scenarios. This method retains the simplicity and operability of empirical models while incorporating surface warming information to quantify and simplify the representation of solar radiation effects, thereby enabling unified calculation and comparison of perceived temperature under both shaded and sunny scenarios.

[0054] The technical concept of this invention lies in the fact that conventional near-surface air temperature is usually measured in a radiation shield or Stevenson screen, reflecting the air temperature under shaded conditions rather than under direct sunlight. This invention defines it as shaded air temperature. Since there is a lack of directly observable standard air temperature quantities under solar exposure scenarios, this invention primarily addresses the problem of constructing temperature characterization quantities for direct solar exposure. Considering that solar radiation primarily acts on the underlying surface, causing it to heat up, and that surface temperature directly reflects the degree of heating and warming characteristics of the underlying surface under solar radiation, surface temperature can be used to characterize the enhancement of the external thermal environment under solar exposure conditions compared to shaded conditions. Furthermore, the heated underlying surface not only affects the near-surface air temperature through sensible heat exchange but also enhances the radiative heat load on the human body through long-wave radiation, thus collectively increasing the level of human heat exposure under solar exposure conditions. Therefore, although surface temperature is not equivalent to air temperature under direct solar exposure, it can reflect the strength of the additional heating effect of solar radiation and can thus serve as an empirical characterization of the degree of enhancement of the external thermal environment under direct solar exposure scenarios.

[0055] It should be noted that surface temperature is not used to directly replace the actual air temperature under direct sunlight, but rather to provide additional warming information caused by solar radiation relative to a shaded background. This is because surface temperature reflects the thermal state of the underlying surface, while air temperature reflects the thermal state of the near-surface air; their physical meanings differ, and the degree to which surface warming is transferred to the near-surface layer is also affected by factors such as wind speed, humidity, underlying surface material, ventilation conditions, and cloud cover. Therefore, this invention does not directly regard surface temperature as air temperature under direct sunlight, but rather as air temperature under shaded conditions. Based on this, additional warming information reflected by surface temperature is introduced, and its contribution to the near-surface thermal environment is characterized by a weighting coefficient, thereby constructing a solar radiation temperature model. .thus, It is not the actual air temperature under direct sunlight, but a comprehensive temperature characterization that takes into account both the background air temperature and the additional heat effect of solar radiation, and the perceived temperature under sunlight is further calculated based on this.

[0056] Example 1

[0057] like Figure 1 and Figure 2 As shown in the figure, the outdoor perceived thermal environment assessment method considering both shaded and sunny scenarios provided in this embodiment includes: firstly, acquiring basic environmental data for the target area. In this embodiment, meteorological station observation data and MODIS surface temperature data for China from 2003 to 2024 are selected as input data to obtain the shaded air temperature corresponding to each station. relative humidity Wind speed and surface temperature The acquired data is processed by removing missing values, checking outliers, and time matching to ensure that the variables correspond to each other on a uniform time scale.

[0058] After data preprocessing, the perceived temperature under shaded conditions is first calculated according to formula (1). And calculate the water vapor pressure according to formula (2). Under direct sunlight, the standard near-surface air temperature is measured in a radiation shield or Stevenson screen, which is closer to the shaded background heat state. However, under direct sunlight, there is a lack of directly observable standard air temperature. Therefore, this embodiment does not directly solve for the complex radiation heat balance, but introduces surface warming information on the basis of the shaded air temperature and constructs the solar radiation temperature according to formula (3). In this embodiment, the weighting coefficient Take 0.5.

[0059] Then, using Instead of the air temperature input in the empirical perceived temperature model, the perceived temperature under sunshine conditions is calculated according to formula (4). Furthermore, calculate according to formulas (5) to (7) respectively. , , Difference index between , , .

[0060] Subsequently, multi-year average statistics are performed to obtain the spatial distribution results of the perceived temperature under shaded conditions, perceived temperature under sunshine conditions, and the difference index in the target area. These spatial distribution results provide the spatial pattern of the outdoor perceived thermal environment in the target area under both shaded and sunny conditions.

[0061] Example 2

[0062] Based on Example 1, the target area can be further divided into different climate zones, and the perceived thermal environment indicators of each zone can be further statistically analyzed. In this example, the target area is divided into a plateau mountain climate zone, a temperate continental climate zone, a temperate monsoon climate zone, and a (sub)tropical monsoon climate zone. The temperate monsoon climate zone is selected as a representative climate zone as an example area, and its... , , The spatial distribution results of the multi-year average are as follows: Figure 3 As shown.

[0063] Furthermore, statistics for each climate zone were compiled on an annual scale. , , The average values ​​of each difference index are used to form a corresponding time change series. After obtaining the time series, trend analysis is performed on each index. Preferably, a linear trend analysis method is used to calculate the slope of each index over time to characterize its direction and magnitude of change; at the same time, the Mann-Kendall trend test is used to determine the significance of the trend of each index, thereby identifying the long-term change characteristics of the outdoor perceived thermal environment and the additional heat effect of direct solar radiation in the target area.

[0064] Through the aforementioned time trend analysis, the interannual variation trend of the perceived thermal environment in the target area under shaded and sunny scenarios can be obtained, and the differences in variation trends between different climate zones can be further identified. The results are as follows: Figure 4 As shown.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the foregoing embodiments have described the present invention in detail, 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 embodiments of the present invention.

[0066] The above descriptions are merely some embodiments of the present invention. Those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. A method for assessing the perceived outdoor thermal environment considering both shaded and sunny scenarios, characterized in that, Includes the following steps: Step S1: Obtain basic environmental data for the target area, including at least shaded temperature. relative humidity Wind speed and surface temperature Furthermore, data preprocessing and time matching processing are performed on the basic environmental data to ensure the correspondence of each variable on a unified time scale. Step S2: Based on the temperature in the shade relative humidity and wind speed An empirical perceived temperature model was used to calculate the perceived temperature under shaded conditions, and the shaded perceived temperature was obtained. ; Step S3, based on shaded temperature and surface temperature To construct a temperature characterization quantity under direct sunlight scenario, namely solar radiation temperature. Among them, sunshine temperature An empirical index used to approximate the intensity of the external thermal environment under solar radiation conditions; Step S4: Set the solar radiation temperature Instead of the air temperature input in the empirical perceived temperature model, the perceived temperature under direct sunlight is calculated to obtain the perceived temperature under sunshine conditions. ; Step S5: Calculate the perceived temperature under sunlight. Shade-induced body temperature Shady temperature The difference , , ; Step S6: Based on the perceived temperature under shade Sunlight perceived temperature The difference between the target area and the outdoor thermal environment assessment results and their spatial distribution characteristics are output.

2. The method as described in claim 1, characterized in that, In step S1, the basic environmental data can come from ground meteorological observation data, remote sensing inversion data, or fused data of the two.

3. The method as described in claim 1, characterized in that, In step S1, data preprocessing of the basic environmental data includes: missing value removal and outlier detection.

4. The method as described in claim 1, characterized in that, In step S2, the perceived temperature under shade for: in, The air temperature is located 2 meters above the ground. For wind speed, This is the actual water vapor pressure.

5. The method as described in claim 4, characterized in that, Actual water vapor pressure According to the temperature in the shade and relative humidity Calculation is performed: in, The relative humidity is 2m above the ground.

6. The method as described in claim 1, characterized in that, In step S3, the solar radiation temperature The calculation method is as follows: in, For surface temperature, The weighting coefficients for the contribution of surface warming to the external thermal environment under direct solar radiation scenarios, and the weighting coefficients The range of values ​​is .

7. The method as described in claim 1, characterized in that, In step S4, the perceived temperature under sunlight The calculation method is as follows: in, For wind speed, This is the actual water vapor pressure.

8. The method as described in claim 1, characterized in that, It also includes step S7: adjusting the perceived temperature under shade. Sunlight perceived temperature The time series of the difference between the time series and the time series are used for trend analysis and the output is visualized.

9. The method as described in claim 8, characterized in that, In step S7, the linear trend analysis method is used to characterize the slope of change, and the Mann-Kendall trend test method is used to test the significance of the trend of change. The linear trend analysis is used to characterize the direction and magnitude of the change of each indicator over time, and the Mann-Kendall trend test is used to determine the significance of the trend of change of each indicator.

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