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三维有云大气辐射变温率数值模拟研究--邻云辐射效应 被引量:2
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作者 章超 王震 +3 位作者 杨军 孙继明 郜海阳 崔生成 《气象学报》 CAS CSCD 北大核心 2016年第4期598-612,共15页
大气数值模式普遍采用一维辐射传输模型,无法表征有云大气中的三维辐射传输过程,从而影响数值模拟乃至数值天气预报的准确性。为评估这种不确定性,研究了水平云体间的三维辐射相互作用及其改变云体热力结构的规律,力求为改进数值模式辐... 大气数值模式普遍采用一维辐射传输模型,无法表征有云大气中的三维辐射传输过程,从而影响数值模拟乃至数值天气预报的准确性。为评估这种不确定性,研究了水平云体间的三维辐射相互作用及其改变云体热力结构的规律,力求为改进数值模式辐射计算方案提供理论依据。选取I3RC PhaseⅡ的典型积云场和层积云场作为试验对象,将云场中心区域云体视为目标云体,周围云体为邻近云体,采用宽带三维辐射传输模式SHDOM模拟长波和短波辐射变温率的空间分布,定量阐明邻近云体对目标云体热力结构的影响。结果表明,邻云在长波区域对目标云体主要起辐射保温的作用,目标云体增温区域集中于邻云一侧的云体表面层,增温强度与云覆盖率和云间距离倒数成正比,最高可达3.08K/h,云体增温的厚度与目标云体液态水含量成反比;在短波区域,邻云同时起散射增温和遮蔽降温的作用,太阳垂直入射时,散射增温效应较弱,变温率空间差异小;当太阳天顶角增大后,遮蔽降温效应逐步起主导作用,造成目标云体被邻云遮挡一侧的表面层明显降温,峰值可达-1.72K/h,数值上甚至超过邻云长波增温效应。总之,邻近云体可以明显改变目标云体的变温率空间分布,引入三维邻云辐射效应对改进大气数值模式辐射计算方案具有重要意义。 展开更多
关键词 三维云场 辐射变温率 长波辐射保温 散射增温 遮蔽降温
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云内辐射传输过程对对流降水过程的影响 被引量:9
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作者 赵春生 丁守国 秦瑜 《自然科学进展》 北大核心 2003年第10期1060-1066,共7页
模拟并讨论了云内辐射传输过程对积云暖云过程和积云冷云过程中的影响.计算结果表明长波辐射使云顶冷却、云底加热,使得整个云体的垂直温度梯度加大,促进了云内的对流运动;短波辐射对云顶加热作用抑制了云中的对流运动.对暖云过程,辐射... 模拟并讨论了云内辐射传输过程对积云暖云过程和积云冷云过程中的影响.计算结果表明长波辐射使云顶冷却、云底加热,使得整个云体的垂直温度梯度加大,促进了云内的对流运动;短波辐射对云顶加热作用抑制了云中的对流运动.对暖云过程,辐射传输方案的引入,使云水、地面降水量都有不同程度的增加,其中,仅考虑长波辐射传输过程时的增加更显著.对冷云过程,长短波辐射的不同作用更为明显:仅考虑长波辐射时,云中的霰量增加;同时考虑长短波辐射时,云中霰量减小.与不考虑辐射过程相比,仅考虑长波辐射传输,可以使地面降水量有不同程度的增加;同时考虑长、短波辐射传输,可以使冷云的地面降水量减少,而使暖云的地面降水略有增加. 展开更多
关键词 数值天气预报 积云 辐射传输过程 对流降水过程 数值模拟 辐射变温率 降水量 降水预报
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Evaluating the impacts of land use and land cover changes on surface air temperature using the WRF-mosaic approach 被引量:2
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作者 ZHAO De-Ming WU Jian 《Atmospheric and Oceanic Science Letters》 CSCD 2018年第3期262-269,共8页
Satellite-derived land surface data in 1980 and 2010 were used to represent land use and land cover(LULC) changes caused by the rapid economic development and human activities that have occurred over the past few de... Satellite-derived land surface data in 1980 and 2010 were used to represent land use and land cover(LULC) changes caused by the rapid economic development and human activities that have occurred over the past few decades in East Asia and China. The effects of LULC changes on the radiation budget and 2-m surface air temperature(SAT) were explored for the period using the Weather Research and Forecasting(WRF) model. The mosaic approach, which considers the N-most abundant land use types within a model grid cell(here, N = 3) and precisely describes the subgridscale LULC changes, was adopted in the integrations. The impacts of LULC changes based on two 36-year integrations showed that SAT generally decreased, with the sole exception being over eastern China, resulting in decreased SAT in China(-0.062 °C) and East Asian land areas(EAL,-0.061 °C). The LULC changes induced changes in albedo, which influenced the radiation budget. The radiative forcings at the top of the atmosphere were-0.56 W m-2 across the whole of China, and-0.50 W m-2 over EAL. Meanwhile, the altered roughness length mainly influenced near-surface wind speeds, large-scale and upward moisture fluxes, latent heat fluxes, and cloud fractions at different altitudes. Though the impacts caused by the LULC changes were generally smaller at regional scales, the values at local scales were much stronger. 展开更多
关键词 Land use and land cover change surface airtemperature ALBEDO radiation budget numerical simulation
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