Numerical Simulation of the Irrigation Effects on Surface Fluxes and Local Climate in Typical Mountain‐Oasis‐Desert Systems in the Central Asia Arid Area. Issue 23 (3rd December 2019)

• Record Type: Journal Article
• Authors: Zhang, Miao; Luo, Geping; Cao, Xiaoshu; Hamdi, Rafiq; Li, Tao; Cai, Peng; Ye, Hui; He, Huili
• Is Part Of: Journal of geophysical research. Volume 124:Issue 23(2019)
• Page Start: 12485
• Page End: 12506
• Publication Date: 2019-12-03
• Subjects: Flood and drip irrigations -- Irrigation effects -- Water‐heat interactions -- Modified WRF‐Noah; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2019JD030507
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: In this study, the Weather Research and Forecasting model was coupled with an improved Noah land surface model (WRF‐Noah) where dynamic flood and drip irrigation processes were implemented firstly. We simulated the different irrigation effects on surface water‐heat processes in a typical mountain‐oasis‐desert system in Central Asia for both wet and drought years, respectively, using the modified WRF‐Noah. The modified WRF‐Noah model can dynamically generate amounts of irrigation in agreement with actual values. The statistically significant decrease in the root mean square error and increase in the Pearson correlation coefficient for the 2‐m temperature (T2), relative humidity (RH), latent heat flux (LE), and precipitation suggest that the modified WRF‐Noah model was improved by implementing irrigation processes. During the irrigation season, flood and drip irrigation decreased the average sensible heat flux by −80.69 and −50.50 W/m 2 and T2 by 1.09 and 0.82 °C over the irrigated area and increased LE by 88.47 and 66.70 W/m 2 and RH by 6.23% and 4.65%, respectively. Throughout the domain, flood irrigation had equivalent or slightly weaker effects on near‐surface temperature and humidity due to the smaller irrigated area. Both flood and drip irrigation increased precipitation throughout the domain, especially in the mountainous area, thereby accelerating the hydrological cycle in the mountain‐oasis‐desert system. The local oasis breeze circulation that plays a role in maintaining the oasis stability is still counteracted by the dominant background circulation even with irrigation processes. Thus, more effort should be exerted to maintain the future sustainability of the oasis. Key Points: The Noah land surface model is updated by adding dynamic flood and drip irrigation processes Both irrigation processes increased precipitation throughout the domain, especially in the mountainous area, thereby accelerating the hydrological cycle in the mountain‐oasis‐desert system The local oasis breeze circulation, which plays a role in maintaining the stability of the oasis, was still counteracted by the dominant background mountain‐plain circulation with dynamic irrigation processes