Wet atmosphere terrain gravity wave parameterization method

Abstract

The invention discloses a wet atmospheric terrain gravity wave parameterization method, which comprises the following steps of: calculating dry adiabatic buoyancy frequency and total density in unsaturated wet air by considering the influence of water vapor, liquid water and solid water; calculating the gravity wave surface stress of the wet atmospheric terrain; calculating a wet atmospheric buoyancy frequency parameter which comprehensively considers a dry adiabatic process and a wet adiabatic process in a terrain gravity wave vertical propagation process; calculating a wet atmosphere buoyancy frequency parameter, a gravity wave amplitude and a local Richardson number layer by layer in an upward propagation process of terrain gravity wave stress; judging whether the terrain gravity wave of the layer is saturated or not; and carrying out numerical simulation on the heavy rainfall event, and analyzing the influence of the existence of water vapor on rainfall. According to the method, the dry air hypothesis in terrain gravity wave parameterization in the numerical mode is processed, the gravity wave surface stress and the vertical propagation process of the stress are better represented, and the performance of the numerical mode is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of numerical weather forecasting, and in particular relates to a parameterization method of wet atmosphere terrain gravity waves. Background Art

[0002] The impact of terrain on the atmosphere has always been a complex and interesting research hotspot in the field of fluid dynamics. When air flows over the surface, terrain can cause atmospheric obstruction or disturbance. These disturbances can cause friction and drag on the airflow and affect the evolution of various weather systems. Numerical weather prediction (NWP) model is currently the main way to make weather forecasts. It uses numerical integration to solve the state of the earth system grid by grid, which is a process of deductive reasoning. However, numerical models can only analyze terrain effects above the grid scale, but cannot describe the impact of small-scale sub-grid terrain on atmospheric circulation.

[0003] Small-scale sub-grid terrain can excite gravity waves under certain atmospheric conditions and propagate vertically upward, increasing in amplitude, breaking when they become unstable, and having significant non-local effects on large-scale circulation in the stratosphere and middle atmosphere. Considering the impact of topographic gravity waves plays an important role in accurately presenting the state of the stratosphere, which is very important for medium-term weather forecasts, seasonal forecasts, and climate predictions. Gravity wave breaking can cause clear-air turbulence, which may affect aircraft flight safety. In the lower troposphere, gravity wave breaking can also produce severe downslope storms. However. It can be seen that small-scale sub-grid terrain has an important impact on atmospheric circulation, so it is necessary to parameterize small-scale sub-grid terrain processes to consider sub-grid effects.

[0004] As early as the 1980s, based on the early mountain wave theory, the influence of gravity waves excited by sub-grid scale terrain was described in NWP models. However, these were limited to two-dimensional single-wave parameterizations and had some assumptions (e.g., stable stratified airflow, neglect of the effect of the earth's rotation, inviscidity, static equilibrium, and dry air assumptions). Lott & Miller (later known as LM97) proposed a new orographic gravity wave drag (OGWD) parameterization scheme for nonlinear low-level mountain drag that was not considered in previous schemes, taking into account the airflow blocking effect caused by sub-grid scale terrain. Subsequently, the OGWD parameterization scheme was applied to multiple NWP models, including ECMWF's IFS, Met Office's UM, JMA's GSM2003, DWD's ICON, and Météo-France's ARPEGE. The OGWD parameterization scheme plays an important role in reducing the errors of tropospheric and stratospheric models and improving the performance of NWP models. However, due to the lack of observations and theoretical constraints on tropospheric and stratospheric terrain drag, the parameterization scheme is generally based on many assumptions and empirical formulas, with large uncertainties and poor constraints, making the parameterization scheme itself one of the error sources of the NWP model. To date, representing unresolved terrain processes in numerical models remains a major challenge. Therefore, the terrain gravity wave parameterization scheme still needs to continue to be de-assumed and de-approximated to become more perfect.

[0005] At present, there is still an important assumption in the OGWD parameterization scheme: dry air approximation. The actual atmosphere contains water vapor, which has an important influence on the state of the atmosphere and is also an important factor affecting climate change. Water vapor can be said to be the core of all key earth atmospheric processes. In the propagation of topographic gravity waves, water vapor also has an important influence on the stability of the atmosphere. When an air mass containing water vapor is disturbed upward, if the water vapor in the air mass condenses and releases latent heat, its heat can partially compensate for the cooling of the air mass due to adiabatic expansion, making the density difference between the moist air mass and the environment smaller than the density difference between the dry air mass and the environment, and the buoyancy of the air mass becomes smaller; for the air mass with a small downward disturbance, the buoyancy will also decrease due to the absorption of latent heat by evaporation, so that the oscillation frequency of moist air is smaller than that of dry air mass. Some scholars have studied the impact of water vapor on the leeward waves trapped in the mountains, and found that changes in water vapor can produce different wave responses in different environments and altitudes. It can be seen that ignoring the influence of water vapor in the existing technology brings errors to the numerical weather forecast model. Therefore, it is necessary to accurately consider the influence of water vapor in the terrain gravity wave parameterization scheme to improve the accuracy of the model. Summary of the invention

[0006] In view of this, the present invention removes the dry air assumption in the terrain gravity wave parameterization scheme, starting from the initial atmospheric motion control equations, considering the influence of water vapor, liquid water and solid water, and using linear gravity wave theory to derive and calculate the surface stress of wet atmospheric terrain gravity waves. In the vertical propagation process of gravity waves, the buoyancy frequency parameters of the wet atmosphere that comprehensively consider the dry adiabatic process and the wet adiabatic process are applied to determine the vertical distribution of gravity wave stress, so as to more accurately describe the sub-grid terrain effect and improve the simulation and prediction capabilities of numerical models in complex terrain areas.

[0007] To achieve the above purpose, the wet atmosphere topography gravity wave parameterization method disclosed in the present application comprises the following steps: Collect site rainfall observation data; The dry air assumption is removed from the topographic gravity wave parameterization scheme, and the unsaturated moist air buoyancy frequency including the humidity effect is calculated in the near-surface moist atmosphere. and the total density of air Calculate the surface stress of wet atmospheric topographic gravity waves based on linear gravity wave theory ; Calculate the buoyancy frequency parameters of the moist atmosphere by comprehensively considering the dry adiabatic process and the wet adiabatic process during the vertical propagation of topographic gravity waves; During the upward propagation of topographic gravity wave stress, the following steps are performed: the buoyancy frequency parameters of the moist atmosphere are calculated layer by layer; the gravity wave amplitude and the local Richardson number are calculated layer by layer; if the local Richardson number is less than the critical value, the gravity wave amplitude where the gravity wave is broken and the gravity wave stress of the layer are calculated; if the local Richardson number is still greater than the critical value, the topographic gravity wave stress of the layer continues to propagate upward; Based on the numerical weather forecast model, the terrain gravity wave parameterization method considering the moist atmosphere is applied to carry out numerical simulation of heavy rainfall events, and the impact of the terrain gravity wave parameterization considering water vapor on rainfall is analyzed.

[0008] Preferably, in the process of the terrain gravity wave stress propagating upward layer by layer, the following steps are performed: a. Horizontal wind field based on the kth layer in the numerical model , wet atmosphere buoyancy frequency , total density of moist air and the gravity wave stress of the next layer Calculate the gravity wave amplitude of this layer ; b. Amplitude of topographic gravity waves based on the layer and wet atmospheric buoyancy frequency , calculate the local Richardson number ; c. According to the local Richardson number By comparing with the critical value, it is determined whether the terrain gravity wave is broken and the terrain gravity wave of this layer is calculated. ; d. Repeat steps a, b, and c until you reach the top of the pattern layer.

[0009] Preferably, the dry air assumption is removed from the terrain gravity wave parameterization scheme, and the total air density of water vapor, liquid water and solid water is included in the control equations of the wet atmosphere motion. and the dry adiabatic buoyancy frequency of unsaturated moist air , total air density The calculation is as follows: ; Where P is the air mass pressure, , denote the dry air pressure and dry air specific gas constant, respectively. , denote the humid air pressure and the humid air specific gas constant, respectively. is the density of liquid water, is the density of solid water, T is the temperature of the air mass, represents the water vapor mixing ratio, represents the total mixing ratio, It represents the ratio of the dry air specific gas constant to the wet air specific gas constant; Dry adiabatic buoyancy frequency of unsaturated moist air The calculation is as follows: ; in, represents the specific heat capacity, is the acceleration due to gravity.

[0010] Preferably, the surface stress of wet atmospheric terrain gravity waves is calculated based on the linear gravity wave theory. : in, is the effective mountain height obtained by subtracting the airflow blockage height from the sub-grid mountain height, is a function of the sharpness of the elliptical mountain range, and is the anisotropy function of the elliptical mountain range, and represent the components parallel and perpendicular to the wind direction, respectively. It is the angle between the mountain azimuth and the wind direction.

[0011] Preferably, the dry adiabatic process and the wet adiabatic process in the wet atmosphere are comprehensively considered during the vertical propagation of the wet atmosphere terrain gravity wave, and the wet atmosphere buoyancy frequency The calculation is as follows: ; Where T is the temperature of the air mass, g is the acceleration due to gravity, is the dry adiabatic lapse rate, is the moist adiabatic lapse rate, represents the saturated mixing ratio, represents the total mixing ratio, represents the latent heat of vaporization, represents the dry air specific gas constant, Indicates height, and are the dry coefficient and the wet coefficient, which are determined by the following formula: ; in is the specific humidity, is the saturated specific humidity, Indicates the saturation regulation coefficient.

[0012] Preferably, during the vertical propagation of wet atmospheric topographic gravity waves, the gravity wave amplitude is calculated as follows: ; in represents the gravity wave stress of the k+1th layer, represents the air density of the kth layer, represents the buoyancy frequency of moist air in the kth layer, represents the wind speed at the kth layer.

[0013] Preferably, during the vertical propagation of wet atmospheric topographic gravity waves, the local Richardson number The calculation is as follows: ; in is the average Richardson number of the airflow, is the Froude number of the airflow.

[0014] Preferably, determining the vertical distribution of gravity wave stress comprises calculating Layer stress: ; in is the amplitude of the gravity wave when it breaks, represents the critical Richardson value, which is iteratively propagated upward gradually to determine the vertical distribution of gravity wave stress.

[0015] The present invention removes the "dry air" assumption, starts from the original atmospheric motion control equations, considers the influence of water vapor, and develops a new wet atmosphere OGWD scheme, which can more accurately describe the sub-grid terrain effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The framework diagram of the present invention; Figure 2 Gravity wave surface stress in the dry atmosphere topography gravity wave parameterization scheme (a) and its difference with the gravity wave surface stress in the wet atmosphere topography gravity wave parameterization scheme (b); Figure 3 The buoyancy frequency (a), local Richardson number (b) and vertical distribution of topographic gravity wave stress (c) during the vertical propagation of topographic gravity waves. The solid line is the parameterization scheme of dry atmosphere topographic gravity waves, the long dashed line is the parameterization scheme of wet atmosphere topographic gravity waves, and the short dashed line is the difference between the two. Figure 4 Numerical simulation results of daily average rainfall in Henan Province, China and its surrounding areas from July 19 to July 21, 2021. Measured rainfall distribution (a), dry topographic gravity wave parameterization scheme (b), wet topographic gravity wave parameterization scheme (c), difference between dry topographic gravity wave parameterization scheme and measured rainfall (d), difference between rainfall in wet topographic gravity wave parameterization scheme and dry topographic gravity wave parameterization scheme (e). DETAILED DESCRIPTION

[0017] The present invention is further explained below by taking the extreme rainfall event in Henan Province, China and its surrounding areas from July 19 to July 21, 2021 as an example and in conjunction with the accompanying drawings, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention are within the scope of protection of the present invention.

[0018] In one embodiment, reference Figure 1 The wet atmosphere topography gravity wave parameterization method disclosed in the present application comprises the following steps: Collect site rainfall observation data; The dry air assumption is removed from the terrain gravity wave parameterization scheme, and the buoyancy frequency of unsaturated moist air in the near-surface moist atmosphere, which includes the effects of water vapor, liquid water and solid water, is calculated. and the total density of air Calculate the surface stress of wet atmospheric topographic gravity waves based on linear gravity wave theory ; Comprehensively consider the dry adiabatic process and wet adiabatic process in the wet atmosphere to calculate the buoyancy frequency of the wet atmosphere ; During the upward propagation of topographic gravity wave stress, the following steps are performed: the buoyancy frequency parameters of the moist atmosphere are calculated layer by layer; the gravity wave amplitude and the local Richardson number are calculated layer by layer; if the local Richardson number is less than the critical value, the gravity wave amplitude where the gravity wave is broken and the gravity wave stress of the layer are calculated; if the local Richardson number is still greater than the critical value, the topographic gravity wave stress of the layer continues to propagate upward; Based on the numerical weather forecast model, the new moist atmosphere topographic gravity wave parameterization method is applied to numerically simulate heavy rainfall events and analyze the impact of water vapor on rainfall.

[0019] In one embodiment, during the process of the terrain gravity wave stress propagating upward layer by layer, the following steps are specifically performed: a. Horizontal wind field based on the kth layer in the numerical model , wet atmosphere buoyancy frequency , total density of moist air and the gravity wave stress of the next layer Calculate the gravity wave amplitude of this layer ; b. Amplitude of topographic gravity waves based on the layer and wet atmospheric buoyancy frequency , calculate the local Richardson number ; c. According to the local Richardson number By comparing with the critical value, it is determined whether the terrain gravity wave is broken and the terrain gravity wave of this layer is calculated. ; d. Repeat steps a, b, and c until you reach the top of the pattern layer.

[0020] In one embodiment, the dry air assumption is removed from the terrain gravity wave parameterization scheme, and the total air density including water vapor, liquid water and solid water is calculated in the governing equations of the wet atmosphere. and the dry adiabatic buoyancy frequency of unsaturated moist air , total air density The calculation is as follows: ; Where P is the air mass pressure, , denote the dry air pressure and dry air specific gas constant, respectively. , denote the humid air pressure and the humid air specific gas constant, respectively. is the density of liquid water, is the density of solid water, T is the temperature of the air mass, represents the water vapor mixing ratio, represents the total mixing ratio, It represents the ratio of the dry air specific gas constant to the wet air specific gas constant; Dry adiabatic buoyancy frequency of unsaturated moist air The calculation is as follows: ; in, represents the specific heat capacity, is the acceleration due to gravity.

[0021] In one embodiment, the surface stress of wet atmospheric terrain gravity waves is calculated based on the linear gravity wave theory. : in, is the effective mountain height obtained by subtracting the airflow blockage height from the sub-grid mountain height, is a function of the sharpness of the elliptical mountain range, and is the anisotropy function of the elliptical mountain range, and represent the components parallel and perpendicular to the wind direction, respectively. It is the angle between the mountain azimuth and the wind direction.

[0022] In one embodiment, the dry adiabatic process and the wet adiabatic process in the wet atmosphere are comprehensively considered during the vertical propagation of the wet atmosphere terrain gravity wave. The calculation is as follows: ; Where T is the temperature of the air mass, g is the acceleration due to gravity, is the dry adiabatic lapse rate, is the moist adiabatic lapse rate, represents the saturated mixing ratio, represents the total mixing ratio, represents the latent heat of vaporization, represents the dry air specific gas constant, Indicates height, and are the dry coefficient and the wet coefficient, which are determined by the following formula: ; in is the specific humidity, is the saturated specific humidity, Represents the saturation regulation coefficient.

[0023] In one embodiment, during the vertical propagation of wet atmospheric terrain gravity waves, the gravity wave amplitude is calculated as follows: ; in represents the gravity wave stress of the k+1th layer, represents the air density of the kth layer, represents the buoyancy frequency of moist air in the kth layer, represents the wind speed at the kth layer.

[0024] In one embodiment, during the vertical propagation of moist atmospheric topographic gravity waves, the local Richardson number The calculation is as follows: ; in is the average Richardson number of the airflow, is the Froude number of the airflow.

[0025] In one embodiment, determining the vertical distribution of gravity wave stress includes calculating Layer stress: ; in is the amplitude of the gravity wave when it breaks, represents the critical Richardson value, which is iteratively propagated upward gradually to determine the vertical distribution of gravity wave stress.

[0026] In this application, the Galactic Global Spectrum Model (YHGSM) for numerical weather prediction developed by the National University of Defense Technology was used, and two sets of numerical experiments (EXP_LM97 and EXP_NEW) were carried out using the LM97 scheme based on the "dry air" hypothesis and the newly proposed moist atmosphere topographic gravity wave parameterization scheme to numerically simulate the extreme rainfall event in Henan, China from July 19 to 21, 2021.

[0027] First, the operation of the numerical model. The reanalysis data with a resolution of TL1279 was obtained according to the ensemble four-dimensional variational data assimilation system. It was used as the initial condition of the numerical model and initialized at 12:00 on July 18, 2021, Universal Time. The model runs for 5 days, covering the entire extreme rainfall period.

[0028] Then, the terrain gravity wave surface stress is calculated. The terrain gravity wave parameterization scheme is called in each integration process of the numerical model, and the surface terrain gravity wave stress is calculated by calculating the buoyancy frequency of unsaturated moist air near the surface and the total air density. Then, the average terrain gravity wave surface stress during extreme rainfall is obtained by averaging. ,like Figure 2 The surface stress in the wet atmosphere topography gravity wave parameterization scheme is greater than that in the dry atmosphere topography gravity wave parameterization scheme.

[0029] Secondly, the vertical distribution of terrain gravity wave stress is calculated. In the process of gravity wave propagation upward vertically, the first step is to comprehensively consider the dry adiabatic process and the wet adiabatic process in the moist atmosphere and calculate the key parameters of the buoyancy frequency of each layer of moist atmosphere. ,like Figure 3 a. The difference between the buoyancy frequency of the wet atmosphere and the buoyancy frequency of the dry atmosphere is mainly reflected in the middle and lower layers of the troposphere, and the wet buoyancy frequency is generally smaller than the dry buoyancy frequency during the vertical propagation of gravity waves upward. The second step is to calculate the local Richardson number ,like Figure 3 b. Local Richardson number in moist atmosphere Less than the local Richardson number in dry atmosphere According to the local Richardson number It is used to judge whether the gravity wave is broken, and the key parameters are used to calculate the gravity wave stress of each layer and determine the vertical distribution of gravity wave stress, such as Figure 3 c. The terrain gravity wave stress in the wet scheme is greater than that in the dry scheme, and the difference between the two is mainly reflected in the middle and lower troposphere. The decay rate of the terrain gravity wave stress with height in the wet scheme is also greater than that in the dry scheme, indicating that the wet scheme will produce stronger terrain gravity wave drag.

[0030] Finally, the numerical simulation results of the moist atmospheric topographic gravity wave parameterization scheme are analyzed. The numerical simulation of the daily average rainfall during the extreme rainfall period in Henan, China and its surrounding areas from July 19 to July 21, 2021 is as follows: Figure 4 As shown. The wet atmosphere topography gravity wave parameterization scheme increases the intensity of the rainfall center and significantly improves the negative deviation of the rainfall center and the positive deviation to the northwest of the rainfall center. The wet atmosphere topography gravity wave parameterization scheme changes the water vapor transport by increasing the drag on the circulation, which increases the net water vapor balance in the heavy rainfall area by about 33%, reduces the average deviation of the daily average rainfall by 14.59%, and improves the proportion of regions with improved daily average rainfall to 74.99%, effectively improving the simulation ability of extreme rainfall events.

[0031] In recent years, extreme weather has occurred frequently. Accurate numerical simulation of extreme rainfall events is an important way to prevent disasters and reduce social impacts, but this is still a challenge. Compared with the prior art, the present invention shows that water vapor has an important influence on the OGWD parameterization in the numerical model, and it will become one of the important error sources of the NWP model based on the "dry air" assumption. The present invention considers the influence of water vapor in the OGWD scheme, processes the dry air assumption of the terrain gravity wave in the numerical model, and can better characterize the vertical propagation process of the gravity wave surface stress and stress excited by the sub-grid terrain by wet air in the actual atmosphere, which helps to improve the numerical simulation of extreme rainfall and improve the simulation of atmospheric circulation, improve the numerical simulation of heavy rainfall and atmospheric circulation, and improve the performance of the numerical weather forecast model.

[0032] As used herein, the word "preferred" is intended to be used as an example, instance, or illustration. Any aspect or design described herein as "preferred" is not necessarily to be construed as being more advantageous than other aspects or designs. On the contrary, the use of the word "preferred" is intended to present concepts in a specific way. The term "or" as used in this application is intended to mean an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X uses A or B" means any one of the naturally included permutations. That is, if X uses A; X uses B; or X uses both A and B, then "X uses A or B" is satisfied in any of the foregoing examples.

[0033] Moreover, although the present disclosure has been shown and described with respect to one or implementations, those skilled in the art will think of equivalent variations and modifications based on the reading and understanding of this specification and the accompanying drawings. The present disclosure includes all such modifications and variations, and is limited only by the scope of the appended claims. In particular, with respect to the various functions performed by the above-mentioned components (such as elements, etc.), the terms used to describe such components are intended to correspond to any component (unless otherwise indicated) that performs the specified function of the component (such as it is functionally equivalent), even if the structure is not equivalent to the disclosed structure of the function in the exemplary implementation of the present disclosure shown herein. In addition, although the specific features of the present disclosure have been disclosed with respect to only one of several implementations, such features can be combined with one or other features of other implementations that may be desired and advantageous for a given or specific application. Moreover, insofar as the terms "including", "having", "containing" or their variations are used in specific embodiments or claims, such terms are intended to be included in a manner similar to the term "comprising".

[0034] The functional units in the embodiments of the present invention may be integrated into a processing module, or each unit may exist physically separately, or multiple or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium. The above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc. The above-mentioned devices or systems may execute the storage method in the corresponding method embodiment.

[0035] To sum up, the above embodiment is an implementation mode of the present invention, but the implementation mode of the present invention is not limited by the embodiment. Any other changes, modifications, substitutions, combinations, and simplifications that deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for parameterizing wet atmospheric topography gravity waves, characterized in that: The following steps are involved: Collect site rainfall observation data; The dry air assumption is removed from the topographic gravity wave parameterization scheme, and the unsaturated moist air buoyancy frequency including the humidity effect is calculated in the near-surface moist atmosphere. and the total density of air Calculate the surface stress of wet atmospheric topographic gravity waves based on linear gravity wave theory ; Calculate the buoyancy frequency parameters of the moist atmosphere by comprehensively considering the dry adiabatic process and the wet adiabatic process during the vertical propagation of topographic gravity waves; During the upward propagation of topographic gravity wave stress, the following steps are performed: the buoyancy frequency parameters of the moist atmosphere are calculated layer by layer; the gravity wave amplitude and the local Richardson number are calculated layer by layer; if the local Richardson number is less than the critical value, the gravity wave amplitude where the gravity wave is broken and the gravity wave stress of the layer are calculated; if the local Richardson number is still greater than the critical value, the topographic gravity wave stress of the layer continues to propagate upward; Based on the numerical weather forecast model, the terrain gravity wave parameterization method considering the moist atmosphere is applied to carry out numerical simulation of heavy rainfall events, and the impact of the terrain gravity wave parameterization considering water vapor on rainfall is analyzed.

2. The wet atmosphere topography gravity wave parameterization method according to claim 1, characterized in that: In the process of topographic gravity wave stress propagating upward layer by layer, the following steps are specifically performed: a. Horizontal wind field based on the kth layer in the numerical model , wet atmosphere buoyancy frequency , total density of moist air and the gravity wave stress of the next layer Calculate the gravity wave amplitude of this layer ; b. Amplitude of topographic gravity waves based on the layer and wet atmospheric buoyancy frequency , calculate the local Richardson number ; c. According to the local Richardson number By comparing with the critical value, it is determined whether the terrain gravity wave is broken and the terrain gravity wave of this layer is calculated. ; d. Repeat steps a, b, and c until you reach the top of the pattern layer.

3. The method for parameterizing wet atmospheric topography gravity waves according to claim 2, characterized in that: Remove the dry air assumption in the topographic gravity wave parameterization scheme and calculate the total air density including water vapor, liquid water and solid water in the governing equations of the moist atmosphere motion and the dry adiabatic buoyancy frequency of unsaturated moist air , total air density The calculation is as follows: ； Where P is the air mass pressure, , denote the dry air pressure and dry air specific gas constant, respectively. , denote the humid air pressure and the humid air specific gas constant, respectively. is the density of liquid water, is the density of solid water, T is the temperature of the air mass, represents the water vapor mixing ratio, represents the total mixing ratio, It represents the ratio of the dry air specific gas constant to the wet air specific gas constant; Dry adiabatic buoyancy frequency of unsaturated moist air The calculation is as follows: ； in, represents the specific heat capacity, is the acceleration due to gravity.

4. The method for parameterizing wet atmospheric topography gravity waves according to claim 3, characterized in that: Calculate the surface stress of wet atmospheric topographic gravity waves based on linear gravity wave theory : ； in, is the effective mountain height obtained by subtracting the airflow blockage height from the sub-grid mountain height, is a function of the sharpness of the elliptical mountain range, and is the anisotropy function of the elliptical mountain range, and represent the components parallel and perpendicular to the wind direction, respectively. It is the angle between the mountain azimuth and the wind direction.

5. The method for parameterizing wet atmospheric topography gravity waves according to claim 4, characterized in that: In the vertical propagation process of wet atmospheric terrain gravity waves, the dry adiabatic process and the wet adiabatic process in the wet atmosphere are comprehensively considered, and the wet atmospheric buoyancy frequency The calculation is as follows: ； Where T is the temperature of the air mass, g is the acceleration due to gravity, is the dry adiabatic lapse rate, is the moist adiabatic lapse rate, represents the saturated mixing ratio, represents the total mixing ratio, represents the latent heat of vaporization, represents the dry air specific gas constant, Indicates height, and are the dry coefficient and the wet coefficient, which are determined by the following formula: ； in is the specific humidity, is the saturated specific humidity, Represents the saturation regulation coefficient.

6. The method for parameterizing wet atmospheric topography gravity waves according to claim 5, characterized in that: During the vertical propagation of wet atmospheric topographic gravity waves, the gravity wave amplitude is calculated as follows: ； in represents the gravity wave stress of the k+1th layer, represents the air density of the kth layer, represents the buoyancy frequency of moist air in the kth layer, represents the wind speed at the kth layer.

7. The method for parameterizing wet atmospheric topography gravity waves according to claim 6, characterized in that: The local Richardson number in the vertical propagation of moist atmospheric topographic gravity waves The calculation is as follows: ； in is the average Richardson number of the airflow, is the Froude number of the airflow.

8. The method for parameterizing wet atmospheric topography gravity waves according to claim 7, characterized in that: Determining the vertical distribution of gravity wave stress includes calculating the Layer stress: ； in is the amplitude of the gravity wave when it breaks, represents the critical Richardson value, which is iteratively propagated upward gradually to determine the vertical distribution of gravity wave stress.

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