Observations of Increased Cloud Cover over Irrigated Agriculture in an Arid Environment
Observations of Increased Cloud Cover over Irrigated Agriculture in an Arid Environment
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DOI：
10.1175/jhm-d-16-0208.1
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发表时间：
2017-07
影响因子：
3.8
通讯作者：
L. Garcia-Carreras;J. Marsham;D. Spracklen
中科院分区：
文献类型：
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作者：
L. Garcia-Carreras;J. Marsham;D. Spracklen
摘要灌溉农业占全球农田面积的 20%，可能会改变当地和全球的气候，但对云和降雨的反馈仍然高度不确定，特别是在干旱地区。干旱地区的不可再生地下水占全球灌溉用水需求的 20%，量化这些反馈对于预测气候变化下的长期用水至关重要。在这里，卫星数据用于显示干旱环境中的灌溉作物如何改变地表特性、云量和降雨模式。尽管反照率较低，农田的地表温度 (LST) 仍比周围环境低 5-7 K，这表明灌溉农田的鲍文比大大降低（潜热通量增加）。白天云量增加高达 15%（相对增加 60%），上午云量增加，下午云峰更大。云量与年际变化显着相关...
AbstractIrrigated agriculture accounts for 20% of global cropland area and may alter climate locally and globally, but feedbacks on clouds and rainfall remain highly uncertain, particularly in arid regions. Nonrenewable groundwater in arid regions accounts for 20% of global irrigation water demand, and quantifying these feedbacks is crucial for the prediction of long-term water use in a changing climate. Here, satellite data are used to show how irrigated crops in an arid environment alter land surface properties, cloud cover, and rainfall patterns. Land surface temperatures (LSTs) over the cropland are 5–7 K lower than their surroundings, despite a lower albedo, suggesting that Bowen ratio is strongly reduced (and latent heat fluxes increased) over the irrigated cropland. Daytime cloud cover is increased by up to 15% points (a relative increase of 60%), with increased cloud development in the morning and a greater afternoon peak in cloud. Cloud cover is significantly correlated with interannual variation...