摘要:通过中亚费尔干纳盆地2007～2011年气候的模拟试验，揭示了新增农田灌溉过程与更新土壤参数对WRF（Weather Research and Forecasting）/Noah模式模拟精度的提升作用。通过对比标准版本与嵌入灌溉过程参数化方案后的WRF/Noah模式的模拟结果，研究发现农业灌溉提升了土壤含水量，导致地表蒸发增强，潜热增加，感热减少，致使近地层大气降温、增湿，这一效应降低了WRF/Noah模拟的暖、干偏差，模拟2 m气温和大气比湿均方根误差分别由6.52°C降低至5.81°C，由1.66 g/kg降低至1.13 g/kg。进而针对WRF默认配置的费尔干纳盆地内土壤数据精度欠佳的问题，再利用国际土壤参比与信息中心（ISRIC）数据（主要是粉砂粘壤土和粉砂壤土）替换了WRF默认的数据（主要是粘土和壤土），降低了土壤凋萎系数，使得有效土壤水增多，缩小了灌溉需水量的模拟误差，并使得蒸散发进一步增强，潜热增多，感热减少，导致近地层降温、增湿，进一步降低了WRF/Noah模拟的暖、干偏差，模拟温度、湿度的均方根误差分别由5.81°C降低至5.46°C，由1.13 g/kg降低至1.08 g/kg。上述结果表明：充分农业灌溉对陆面过程产生影响，以及采用高精度的土壤数据能够显著提高WRF/Noah模式在中亚费尔干纳盆地的模拟精度。
关键词:WRF/Noah模式/
灌溉/
土壤质地/
模拟误差
Abstract:This study aims to identify the improvements of WRF/Noah simulations for the Fergana basin in central Asia resulting from the implementation of an irrigation scheme and update of soil data in climate simulations for the period of 2007–2011. First, simulations with the WRF/Noah model within which an irrigation scheme was implemented were compared with those involving the default WRF/Noah model. The results indicated that the irrigation enhanced soil moisture and thus intensified evapotranspiration and latent heat and reduced sensible heat; under these conditions, cooling and wetting effects occurred on surface air. The warming and drying biases were partly corrected. The root mean squared error (RMSE) of air temperature at 2 m decreased from 6.52°C to 5.81°C. Meanwhile, the RMSE of the specific humidity of air at 2 m decreased from 1.66 g/kg to 1.13 g/kg. Second, on the basis of the implemented irrigation scheme, the soil texture and hydraulic parameters were updated with the data from the International Soil Reference and Information Centre. Clay and loam were replaced with silty clay loam and silty loam for the plain area of the Fergana basin. Hence, the wilting point declined, and the amount of available water in the soil increased. The bias of the water demand of the simulated irrigation was partly corrected. Moreover, the evapotranspiration and latent heat intensified, and the sensible heat decreased. Hence, intensified cooling and wetting effects were observed on surface air. The warming and drying biases were corrected further. Under these conditions, the RMSE of air temperature at 2 m decreased from 5.81°C to 5.46°C whereas, that of the specific humidity of air at 2 m decreased from 1.13 g/kg to 1.08 g/kg. These findings suggest that implementing an irrigation scheme and updating soil data may improve the performance of the WRF/Noah model for the Fergana basin in central Asia.
Key words:WRF/Noah model/
Irrigation/
Soil texture/
Modelling bias
PDF全文下载地址:
http://www.iapjournals.ac.cn/qhhj/article/exportPdf?id=6f62dafb-3751-412f-85b6-3f312ee10505
