| Effect of Mesoscale Land Use Change on Characteristics of Convective Boundary Layer: Semi-Idealized Large Eddy Simulations over Northwest China | |
| Alternative Title | Effect of Mesoscale Land Use Change on Characteristics of Convective Boundary Layer: Semi-Idealized Large Eddy Simulations over Northwest China |
| Cao Bangjun1; Zhang Shuwen2; Li Deqin3; Li Yanlin2; Zhou Linfan2; Wang Jiemin4 | |
| 2018 | |
| Source Publication | JOURNAL OF METEOROLOGICAL RESEARCH
 |
| ISSN | 2095-6037 |
| Volume | 32Issue:3Pages:421-432 |
| Abstract | Although large-scale topography and land use have been properly considered in weather and climate models, the effect of mesoscale and microscale heterogeneous land use on convective boundary layer (CBL) has not been fully understood yet. In this study, the influence of semi-idealized strip-like patches of oases and deserts, which resemble irrigated land use in Northwest China, on the CBL characteristics, is investigated based on the Weather Research and Forecasting (WRF)-large eddy simulation (LES) driven by observed land surface data. The influences of soil water content in oases on aloft CBL flow structure, stability, turbulent kinetic energy (TKE), and vertical fluxes are carefully examined through a group of sensitivity experiments. The results show that secondary circulation (SC)/turbulent organized structures (TOS) is the strongest/weakest when soil water content in oases is close to saturation (e.g., when the oases are irrigated). With the decrease of soil water content in oases (i.e., after irrigation), SC (TOS) becomes weak (strong) in the lower and middle CBL, the flux induced by SC and TOS becomes small (large), which has a dramatic impact on point measurement of eddy covariance (EC) fluxes. The flux induced by SC and TOS has little influence on EC sensible heat flux, but great influence on EC latent heat flux. Under this circumstance, the area averaged heat flux cannot be represented by point measurement of flux by the EC method, especially just after irrigation in oases. Comparison of imbalance ratio (i.e., contribution of SC and TOS to the total flux) reveals that increased soil moisture in oases leads to a larger imbalance ratio as well as enhanced surface heterogeneity. Moreover, we found that the soil layer configuration at different depths has a negligible impact on the CBL flux properties. |
| Other Abstract | Although large-scale topography and land use have been properly considered in weather and climate models,the effect of mesoscale and microscale heterogeneous land use on convective boundary layer (CBL) has not been fully understood yet.In this study,the influence of semi-idealized strip-like patches of oases and deserts,which resemble irrigated land use in Northwest China,on the CBL characteristics,is investigated based on the Weather Research and Forecasting (WRF)-large eddy simulation (LES) driven by observed land surface data.The influences of soil water content in oases on aloft CBL flow structure,stability,turbulent kinetic energy (TKE),and vertical fluxes are carefully examined through a group of sensitivity experiments.The results show that secondary circulation (SC)/turbulent organized structures (TOS) is the strongest/weakest when soil water content in oases is close to saturation (e.g.,when the oases are irrigated).With the decrease of soil water content in oases (i.e.,after irrigation),SC (TOS) becomes weak (strong) in the lower and middle CBL,the flux induced by SC and TOS becomes small (large),which has a dramatic impact on point measurement of eddy covariance (EC) fluxes.The flux induced by SC and TOS has little influence on EC sensible heat flux,but great influence on EC latent heat flux.Under this circumstance,the area averaged heat flux cannot be represented by point measurement of flux by the EC method,especially just after irrigation in oases.Comparison of imbalance ratio (i.e.,contribution of SC and TOS to the total flux) reveals that increased soil moisture in oases leads to a larger imbalance ratio as well as enhanced surface heterogeneity.Moreover,we found that the soil layer configuration at different depths has a negligible impact on the CBL flux properties. |
| Keyword | BALANCE CLOSURE PROBLEM SURFACE INHOMOGENEITIES HETEROGENEOUS SURFACES COVARIANCE FLUXES IMBALANCE PROBLEM ENERGY IMBALANCE MODEL SCALE STRATOCUMULUS CIRCULATIONS oasis and desert land surface heterogeneity large eddy simulation soil water content secondary circulation turbulent organized structure |
| Indexed By | CSCD |
| Language | 英语 |
| Funding Project | [National Key Research and Development Program of China] ; [National Natural Science Foundation of China] ; [Specialized Research Fund for the Doctoral Program of Higher Education] |
| CSCD ID | CSCD:6277735 |
| Citation statistics |
Cited Times:3[CSCD]
[CSCD Record]
|
| Document Type | 期刊论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/154419 |
| Collection | 中国科学院金属研究所 |
| Affiliation | 1.成都学院 2.兰州大学 3.中国科学院金属研究所 4.中国科学院 |
| Recommended Citation GB/T 7714 | Cao Bangjun,Zhang Shuwen,Li Deqin,et al. Effect of Mesoscale Land Use Change on Characteristics of Convective Boundary Layer: Semi-Idealized Large Eddy Simulations over Northwest China[J]. JOURNAL OF METEOROLOGICAL RESEARCH,2018,32(3):421-432. |
| APA | Cao Bangjun,Zhang Shuwen,Li Deqin,Li Yanlin,Zhou Linfan,&Wang Jiemin.(2018).Effect of Mesoscale Land Use Change on Characteristics of Convective Boundary Layer: Semi-Idealized Large Eddy Simulations over Northwest China.JOURNAL OF METEOROLOGICAL RESEARCH,32(3),421-432. |
| MLA | Cao Bangjun,et al."Effect of Mesoscale Land Use Change on Characteristics of Convective Boundary Layer: Semi-Idealized Large Eddy Simulations over Northwest China".JOURNAL OF METEOROLOGICAL RESEARCH 32.3(2018):421-432. |
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