Page 250 - 《高原气象》2025年第5期

高 原 气 象 44 卷
1368

Sensitivity Study of a Parameterised Scheme for Land Surface
Latent Heat Flux based on BCC_AVIM

LIN Zhaoyu ， ZHANG Yu ， WU Tongwen ， SU Youqi ， WANG Shaoying ， MA Xiangyi 4
1
3
1
2
1
（1. College of Atmospheric Sciences， Chengdu University of Information Technology /Chengdu Plain Urban Meteorology and
Environment Sichuan Provincial Field Scientific Observation and Research Station， Chengdu 610225， Sichuan， China；
2. Earth System Numerical Prediction Center， China Meteorological Administration， Beijing 100081， China；
3. Key Laboratory of Cryospheric Science and Frozen Soil Engineering， Northwest Institute of Eco-Environment and
Resources， Chinese Academy of Sciences， Lanzhou 730000， Gansu， China；
4. College of Optoelectronic Engineering， Chengdu University of Information Technology /Chengdu Plain Urban Meteorology and
Environment Sichuan Provincial Field Scientific Observation and Research Station， Chengdu 610225， Sichuan， China）

Abstract： The BCC_AVIM model neglects the effects of molecular diffusion rate， vegetation litter and dry sur‐
face layer thickness on water vapour conductivity in the simulation of latent heat fluxes at the land surface. Based
on this， this paper considers the above detailed physical processes for the simulation of latent heat fluxes at the
land surface， and focuses on the effects of these processes on the simulation. The physical processes considered
mainly include （1） the diffusion rate of molecules through the soil pores to the drying surface layer and the effect
of plant apoplastic cover on the water vapour conductivity （Sakaguchi and Zeng， 2009， hereafter referred to as
the S-Z scheme）； （2） the effect of the thickness of the drying surface layer of soil on the water vapour conductiv‐
ity （Swenson and Lawrence， 2014， hereafter referred to as the S-L scheme）； and （3） the effect of physical pro‐
cesses on water vapour conductivity in the combined S-Z and S-L schemes， hereafter referred to as the SZ-SL
scheme. In order to better study its sensitivity in different subsurfaces， observations from the flat and uniform al‐
pine meadow Maqu station and the complex topography of Si'e Mountain station in Southern Sichuan Forest were
selected to examine the simulated effects of different parameterisation schemes. The results are as follows： （1）
The BCC_AVIM model can better reproduce the trends of soil temperature and humidity， sensible latent heat
fluxes and other elements at Si'e Mountain and Maqu stations， but the simulated values deviate from the mea‐
sured values to a certain extent； （2） Based on the BCC_AVIM model， the simulated latent heat fluxes at the two
stations are significantly improved by the introduction of more detailed physical processes， with the simulated re‐
sults of the S-Z scheme being the closest to the measured values， and the simulated results of the S-Z scheme be‐
ing the closest to the measured values. were closest to the measured values， with the Pearson's correlation coeffi‐
cient （R） of Si'e Mountain station improved from 0. 68 to 0. 74， the mean absolute percentage error （MAPE） re‐
-2
duced by 10. 7%， and the root mean square error （RMSE） reduced by 4. 0 W·m ； the R of Maqu station was
improved from 0. 15 to 0. 62， the MAPE was reduced by 5. 7%， and the RMSE was reduced by 11. 2 W·m ；
-2
（3） the simulation results of the two stations' soil temperature and humidity simulation results show that com‐
pared with the original scheme， the scheme after considering more detailed physical processes increases the simu‐
lated values of soil temperature and soil humidity and enhances the correlation with the measured values， of
which the S-Z scheme is the optimal scheme for soil temperature simulation at the two stations， the S-L scheme
is the optimal parameterization scheme for soil humidity simulation at Si'e Mountain station， and the SZ-SL
scheme is the optimal parameterization scheme for soil moisture simulation at Maqu station. scheme； （4） by con‐
sidering more detailed physical processes， not only the simulation accuracy of latent heat fluxes is significantly
improved， but also the simulation ability of soil temperature and soil moisture is enhanced， but the improvement
of sensible heat fluxes is still limited.
Key words： BCC_AVIM model； latent heat flux； parameterization