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基于2001～2018年中分辨率成像光谱仪（MODIS）探测的白天地面温度（简称MODIS 白天地温）资料,与青藏高原（简称高原）122个气象站点观测的最高气温资料,在年尺度上评估了MODIS 白天地温在高原的适用性,研究了高原五个干湿分区下MODIS 白天地温的海拔依赖型变暖特征,得到以下主要结论:（1）MODIS白天地温能够基本再现观测的最高气温的时空以及海拔依赖型变暖特征;（2）高原整体上,MODIS白天地温存在显著的海拔依赖型变暖特征,平均海拔每增加100 m,其趋势增加0.02°C (10a)?1,且受积雪—反照率反馈主导;（3）干湿分区下,海拔依赖型变暖特征在高原表现为偏湿润地区强于偏干旱地区;季风区强于西风区。海拔依赖型特征强弱:半湿润地区＞湿润半湿润地区＞半干旱地区＞湿润地区＞干旱地区。平均海拔每增加100 m,以上区域的地温趋势分别增加0.06,0.03,0.03,0.01,0.01°C (10a)?1。半湿润和湿润半湿润地区年均温在0°C左右,在气候变暖背景下积雪—反照率反馈作用最为强烈,是其海拔依赖型变暖的主导因素;干旱与半干旱地区年均温相对更低,气候变暖程度对积雪影响相对较小,积雪—反照率反馈作用被限制,但仍对上述地区的海拔依赖型变暖起主导作用;而湿润地区的积雪覆盖率的上升可能是由于降雪（固态降水）增加抵消了积雪融化损耗,云辐射、水汽等其他因素主导了其海拔依赖型变暖。 相似文献
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应用MODIS地表反照率产品MCD43C3,结合青藏高原自然带数据、积雪覆盖率和植被指数数据,采用一元线性回归方法分析了2000~2016年青藏高原地表反照率的分布及变化特征,结果表明:1）高原地表反照率空间分布差异大,整体上东南部低、西北部高,受地形和地表覆盖影响较大。2）高原地表反照率四季的空间分布变化明显,高海拔山脉和高寒灌丛草甸是高原地表反照率年内和年际变化的敏感地区。3）高原地表反照率年变化介于0.19~0.26,一定程度上表现为“双峰单谷”型,与地表覆盖类型的季节变化密切相关。4）高原地表反照率年际变化整体呈缓慢波动减小的趋势,平均变率约为－0.4×10-3 a-1,减小的区域约占高原总面积的66%,川西 —藏东针叶林带的西南部地区减小得最快,减小速率超过1.0×10-2 a-1。5）高原地表反照率减小与冰川消融和积雪减少密切相关,高原植被覆盖改善也是一个重要因素。 相似文献
4.
对比分析了青藏高原MODIS地表反照率产品和GLASS地表反照率产品的空间分布连续性、高质量反演结果的比例,应用青藏高原CAMP/Tibet试验期间的高精度观测数据评估了两种产品的精度,通过人工目视解译MODIS地表反射率图像并结合MODIS积雪产品分析了影响两种产品精度的原因,结果表明：1）GLASS地表反照率产品具有比MODIS地表反照率产品更好的空间分布连续性和更高的反演质量;2）绝大多数时段内两种产品都能与地面观测结果保持较好的一致性,能准确地反映地表反照率的异常变化过程;3）局地积雪是影响两种产品精度的重要因素之一;4）积雪条件下,GLASS地表反照率反演算法比MODIS地表反照率反演算法更具优势。研究结果有助于促进人们对地表反照率卫星遥感反演产品的认识,改进青藏高原地表反照率卫星遥感反演算法,提高青藏高原地表反照率卫星遥感反演结果的精度、反演质量和空间分布连续性。 相似文献
5.
Yulong Ren Yaohui Li Zhaoxia Pu Tiejun Zhang Haixia Duan Wei Wang 《Acta Meteorologica Sinica》2018,32(5):758-767
Biogeophysical effects of land use and land cover (LULC) changes play a significant role in modulating climate on various spatial scales. In this study, a set of recent LULC products with a spatial resolution of 500 m was developed in China for update in RegCM4 (regional climate model version 4). Two sets of comparative numerical experiments were conducted to study the effects of LULC changes on near-surface temperature simulation. The results show that after LULC changes, areas of crops and mixed woodlands as well as urban areas increase over entire China, accompanied with greatly expanded mixed farming and forests/field mosaics in southern China, and reduced areas of 1) irrigated crops and short grasses in northern China and the Tibetan Plateau, and 2) semi-desert and desert in northwestern China. Improvements in the LULC data clearly result in more accurate simulations of the near-surface temperature. Specifically, increasing latent heat and longwave albedo due to enhanced LULC in certain areas lead to reduction in land surface temperature (LST), while changes in shortwave albedo and sensible heat also exert a great influence on the LST. Overall, these parameter adjustments reduce the biases in near-surface temperature simulation. 相似文献
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钟强 《Acta Meteorologica Sinica》1998,(2)
The combination of field experiments and satellite observations is the fundamental way tounderstand the characteristics of spatial-temporal variation in surface albedo over the Tibetan(Qinghai-Xizang) Plateau. Under the condition without snow cover, the relatively regular annualvariation cycle of the surface albedo can be expressed by an empirical formula. The effect of snowcover on the surface albedo in winter can be expressed by introducing two variables of snow forcingand sensitivity parameter. The existing satellite retrieved results of surface albedo may provide thedigital grid data for describing the geographical distribution. However, some satellite retrievedsurface albedos available over the Tibetan Plateau are obviously too low in winter. Taking thesatellite derived results in summer as the background field representative of geographicaldistribution and combining the empirical formula of annual cycle based on the surface observations,a dynamic model of surface albedo is developed for the need of modeling the climatic influence ofthe underlying surface forcing of the Tibetan Plateau. 相似文献
7.
Zhong Qiang 《Acta Meteorologica Sinica》1998,12(2):177-189
The combination of field experiments and satellite observations is the fundamental way to understand the characteristics of spatial-temporal variation in surface albedo over the Tibetan(Qinghai-Xizang) Plateau. Under the condition without snow cover, the relatively regular annual variation cycle of the surface albedo can be expressed by an empirical formula. The effect of snow cover on the surface albedo in winter can be expressed by introducing two variables of snow forcing and sensitivity parameter. The existing satellite retrieved results of surface albedo may provide the digital grid data for describing the geographical distribution. However, some satellite retrieved surface albedos available over the Tibetan Plateau are obviously too low in winter. Taking the satellite derived results in summer as the background field representative of geographical distribution and combining the empirical formula of annual cycle based on the surface observations,a dynamic model of surface albedo is developed for the need of modeling the climatic influence of the underlying surface forcing of the Tibetan Plateau. 相似文献
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青藏高原积雪对气候影响的研究进展和问题 总被引：15，自引：2，他引：13
系统地回顾了青藏高原积雪对天气气候影响的国内外研究进展,并对研究中存在的一些问题做出了评述。认识到积雪增加将导致亚洲夏季风减弱或爆发推迟,这是通过积雪-季风关系实现的。对反射率和融雪的相对重要性,尚未有一致意见。高原积雪作为一种重要的陆面强迫因子,和副高、阻高、冬夏季风、ENSO、海温等影响中国天气气候的因子有密切关系。在全球变暖的背景下,青藏高原积雪却出现了增加,对这一问题的研究具有重要的现实意义。高原积雪年代际变化的研究,有助于揭示我国近年来“南涝北旱”雨型的原因,同时有利于雨型反转时间的预测。 相似文献
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利用MODIS卫星资料反演中国地区晴空地表短波反照率及其特征分析 总被引：16，自引：0，他引：16
利用MODIS地表双向反照率产品(MOD43B1),结合地表海拔高度和地表覆盖类型资料,计算并分析了中国地区晴空反照率的时空分布,以及地表反照率与地形和地表覆盖的关系.首先,利用改则自动气象站的地基观测对MODIS地表反照率进行了对比验证.验证结果表明卫星观测可以较好地反映反照率随时间的变化,MODIS地表反照率与地表实测反照率符合较好.年平均地表反照率与海拔高度有很好的相关,反照率的高值出现在高海拔山区.冬春季节,我国高海拔山区因积雪覆盖成为反照率的高值区;夏秋季节,地表反照率主要受地表土壤湿度和植被盖度的影响,沙地和沙漠地带反照率最高.最后,计算了中国典型地表类型的反照率随时间的变化,结果表明大部分地表类型的反照率具有较大的时间变化,地表反照率在春秋季节较大,夏季反照率较小. 相似文献
10.
利用2000～2016年MODIS地表反照率和ECMWF/ERA-Interim再分析资料,选取有代表性的高原季风指数DPMI,统计分析了青藏高原地表反照率与高原季风之间的联系,结果表明:1)11月高原地表反照率大小与次年高原夏季风爆发存在密切关系:11月高原地表反照率偏低(高),次年4月高原夏季风爆发偏早(晚),强度偏强(弱)。2)可能的影响机制为:当前期11月高原地表反照率偏低时,后期高原主体对大气的感热加热信号更强,从而引起4月高原上空近地面层上升运动明显加强,这有利于热量向高空传输,导致对流层加热作用加强,高原上空对流层温度偏高,使得高原季风环流系统加强,最终导致高原季风季节变化相应提前;反之亦然。 相似文献
11.
青藏高原地表特征时空分布 总被引：12，自引：3，他引：9
通过利用地理信息数据库、卫星反演参数、气象观测数据,分析了我国青藏高原地区地表植被覆盖、地表反照率分布、地表蒸发分布、地表积雪分布.结果显示,随着青藏高原地表年平均气温的显著升高,青藏高原部分区域地表覆盖特征也发生了改变.在青藏高原南缘湿润大区降水充分地区,地表反照率相对较低,潜热蒸发量最大,1982～2000年期间地表植被覆盖呈明显增加趋势.青藏高原地区积雪覆盖在各个气候区域也呈现同步变化特征,自1970～1989期间,降雪量呈持续增加趋势,但之后至2000年期间,全区降雪量呈下降趋势,其中积雪覆盖变化最强烈的时段发生在10月～4月之间,变化幅度最大的区域位于青藏高原的东南部区域. 相似文献
12.
Diurnal and Seasonal Variation of Clear-Sky Land Surface Temperature of Several Representative Land Surface Types in China Retrieved by GMS-5 总被引：1，自引：0，他引：1 
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下载免费PDF全文 The retrieved results in this paper by GMS-5/VISSR thermal infrared data with single time/dual channel Split-Window Algorithm reveal the characteristics of diurnal and seasonal variation of clear-sky land surface temperature (LST) of several representative land surface types in China,including Tarim Basin,Qinghai- Tibetan Plateau,Hunshandake Sands,North China Plain,and South China.The seasonal variation of clear-sky LST in above areas varies distinctly for the different surface albedo,soil water content,and the extent of influence by solar radiation.The monthly average diurnal ranges of LST have two peaks and two valleys in one year.The characteristics of LST in most land of East Asia and that of sea surface temperature (SST) in the south of Taiwan Strait and the Yellow Sea are also analyzed as comparison.Tarim Basin and Hunshandake Sands have not only considerable LST diurnal cycle but also remarkable seasonal variation. In 2000,the maximum monthly average diurnal ranges of LST in both areas are over 30 K,and the annual range in Hunshadake Sands reaches 58.50 K.Seasonal variation of LST in the Qinghai-Tibetan Plateau is less than those in East Asia,Tarim Basin,and Hunshandake Sands.However,the maximum diurnal range exists in this area.The yearly average diurnal range is 28.05 K in the Qinghai-Tibetan Plateau in 2000.The characteristics of diurnal,seasonal,and annual variation from 1998 to 2000 are also shown in this research. All the results will be valuable to the research of climate change,radiation balance,and estimation for the change of land surface types. 相似文献
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Snowfall and the subsequent evolution of the snowpack have a large effect on the surface energy balance and water cycle of the Tibetan Plateau (TP). The effects of snow cover can be represented by the WRF coupled with a land surface scheme. The widely used Noah scheme is computationally efficient, but its poor representation of albedo needs considerable improvement. In this study, an improved albedo scheme is developed using a satellite-retrieved albedo that takes snow depth and age into account. Numerical experiments were then conducted to simulate a severe snow event in March 2017. The performance of the coupled WRF/Noah model, which implemented the improved albedo scheme, is compared against the model’s performance using the default Noah albedo scheme and against the coupled WRF/CLM that applied CLM albedo scheme. When the improved albedo scheme is implemented, the albedo overestimation in the southeastern TP is reduced, reducing the RMSE of the air temperature by 0.7°C. The improved albedo scheme also attains the highest correlation between the satellite-derived and the model-estimated albedo, which provides for a realistic representation of both the snow water equivalent (SWE) spatial distribution in the heavy snowbelt (SWE > 6 mm) and the maximum SWE in the eastern TP. The underestimated albedo in the coupled WRF/CLM leads to underestimating the regional maximum SWE and a consequent failure to estimate SWE in the heavy snowbelt accurately. Our study demonstrates the feasibility of improving the Noah albedo scheme and provides a theoretical reference for researchers aiming to improve albedo schemes further. 相似文献
14.
A recent modelling study has shown that precipitation and runoff over land would increase when the reflectivity of marine clouds is increased to counter global warming. This implies that large scale albedo enhancement over land could lead to a decrease in runoff over land. In this study, we perform simulations using NCAR CAM3.1 that have implications for Solar Radiation Management geoengineering schemes that increase the albedo over land. We find that an increase in reflectivity over land that mitigates the global mean warming from a doubling of CO2 leads to a large residual warming in the southern hemisphere and cooling in the northern hemisphere since most of the land is located in northern hemisphere. Precipitation and runoff over land decrease by 13.4 and 22.3%, respectively, because of a large residual sinking motion over land triggered by albedo enhancement over land. Soil water content also declines when albedo over land is enhanced. The simulated magnitude of hydrological changes over land are much larger when compared to changes over oceans in the recent marine cloud albedo enhancement study since the radiative forcing over land needed (?8.2?W?m?2) to counter global mean radiative forcing from a doubling of CO2 (3.3?W?m?2) is approximately twice the forcing needed over the oceans (?4.2?W?m?2). Our results imply that albedo enhancement over oceans produce climates closer to the unperturbed climate state than do albedo changes on land when the consequences on land hydrology are considered. Our study also has important implications for any intentional or unintentional large scale changes in land surface albedo such as deforestation/afforestation/reforestation, air pollution, and desert and urban albedo modification. 相似文献
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青藏高原积雪深度对延伸期预报技巧的影响 总被引：1，自引：0，他引：1
高原积雪是重要的陆面因子,其变化的时间尺度长于大气而短于海洋。本文利用国家气候中心第二代月动力延伸期预测模式（DERF2.0）历史回报资料与被动微波资料（SMMR）、被动微波成像专用传感器（SSM/I）数据反演的逐日雪深资料,分析了1983~2014年冬季和春季转换季节高原积雪对热带外地区延伸期尺度预测技巧的影响。结果表明,高原积雪异常年动力模式在高原积雪显著影响的青藏高原地区、贝加尔湖地区和北太平洋地区预报技巧明显高于正常年份。随着预报时效的延长,高原积雪偏多年的技巧衰减最慢、其次为积雪偏少年,积雪正常年最快,表明高原积雪异常年可预报时效更长,且高原积雪异常对预报技巧的改善在第1候的预报中就显现出来,尤其是积雪偏多年,其影响时段明显要早于海洋。结果显示高原积雪对延伸期预报技巧有重要贡献,暗示高原积雪异常为东亚延伸期预报的潜在可预报源。 相似文献
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文章讨论了利用ISCCP卫星观测资料确定青藏高原地区地表反射率的方法，在无积雪地区和季节，地表反射率可以ISCCP可见光反射率为基础，在模式计算过程中，假定紫外反射率以及红外与可见光反射率的比值分别为常数。敏感性试验表明，由这两个假设所产生的误差并不显著。在有积雪地区或季节，地表平均反射率可直接由ISCCP可见光反射率表示。试验结果与地面实际观测作了比较，除沙漠区外，两者比较一致。文中还计算了高原晴天行星反射率。经与ERBE卫星观测比较，发现从5月至9月高原周围沙漠区气溶胶对辐射平衡有较显著的影响。而在其 相似文献
17.
Wu Yang Huang Anning Lazhu Yang Xianyu Qiu Bo Wen Lijuan Zhang Zhiqi Fu Zhipeng Zhu Xueyan Zhang Xindan Cai Shuxin Tang Yong 《Climate Dynamics》2020,55(9-10):2703-2724
A series of model sensitivity simulations are carried out to calibrate and improve the Weather Research and Forecasting Model coupled with a one-dimensional lake model (WRF-Lake) based on observations over Lake Nam Co. Using the default lake model parameters, the solution of WRF-Lake exhibits significant biases in both the lake thermodynamics and regional climatology, i.e., higher lake surface temperature (LST), earlier onset of summer thermal stratification, and overestimated near-surface air temperature and precipitation induced by the lake’s excessive warming and moistening impacts. The performance of WRF-Lake is improved through adjusting the initial lake temperature profile, the temperature of maximum water density (Tdmax), the surface roughness length, and the light extinction coefficient. Results show that initializing the water temperature with spring observation mitigates the LST overestimation and reduces the timing error of the onset of thermal stratification. By further adjusting Tdmax from 4 °C to the observed value of 3.5 °C, the LST increase from June to mid-July is enhanced and the buildup of thermal stratification is more accurately predicted. Through incorporating the parameterized surface roughness length and decreasing the light extinction coefficient, the model better reproduces the observed daily evolution of LST and vertical lake temperature profile. The calibrated WRF-Lake effectively mitigates the overestimation of over-lake air temperature at 2 m height and precipitation over regions downwind the lake. This suggests that an improved lake scheme within the coupled WRF-Lake is essential for realistically simulating the lake–air interactions and the regional climate over the lake-rich Tibetan Plateau.
相似文献18.
青藏高原GLASS地表反照率产品精度分析 总被引：2，自引：0，他引：2
应用2003年青藏高原3个站点的地表反照率观测结果,对比分析了GLASS(Global LAnd Surface Satellites)地表反照率1 km×1 km分辨率产品的精度,结果表明,GLASS黑空反照率、白空反照率与地表反照率地面观测结果的总体变化趋势基本一致,能够有效地反映实际地表状态的变化;局地积雪和云覆盖对GLASS地表反照率产品的精度影响较大,云覆盖导致GLASS地表反照率可能比实际地表反照率高;消除云覆盖和局地积雪的影响后,GLASS黑空反照率、白空反照率与地表反照率地面观测结果的均方根误差显著降低,分别为0.0155和0.0190。 相似文献
19.
在参考国内外卫星遥感反演地表反照率方法的基础上,提出了一种反演多云地区地表反照率的新方法,称之为组合反演法。对于受云影响而无法获得足够的晴空观测数据的像素点,在遥感地表分类数据和归一化植被指数（NDVI） 数据的辅助下,在其周围的有限范围内选择与其具有相同BRDF形状的像素点,将它们在观测角度上互为补充的晴空观测数据组合成对同一个BRDF形状的一组多角度观测数据,达到一定数量后直接利用线性的RossThick-LiSparse互易核驱动模型反演二向反射分布函数（BRDF）参数。然后,根据“16天”期间平均的当地正午太阳高度角计算反照率。选择青藏高原地区2004年6～8月间5组“16天”的Terra MODIS数据进行的反演试验表明,该方法不仅具有反演多云地区地表反照率的能力,而且能够更好地反映实际的地表信息,反演结果的精度与美国MOD43产品的精度相当。 相似文献
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GMS 5反演中国几类典型下垫面晴空地表温度的日变化及季节变化 总被引：4，自引：1，他引：3
文中利用单时相双光谱分裂窗算法以GMS 5/VISSR红外资料反演地表温度,揭示了中国几类典型下垫面晴空地表温度的日变化及季节变化特征.塔里木盆地、青藏高原、浑善达克沙地、华北平原北部、华南部分地区因地表反射率、土壤含水量、受太阳辐射影响程度不同等地表温度季节变化差异很大,月平均地表温度日较差一年内基本上呈双峰双谷型.作为比较,东亚部分陆地的地表温度与台湾海峡南部、黄海的海表温度及其日变化、季节变化一并进行了分析.塔里木盆地、浑善达克沙地不仅具有强烈的日变化,而且季节变化也显著.2000年两地月平均地表温度日较差最大值超过30 K,浑善达克沙地的年较差高达58.50 K.青藏高原地表温度季节变化小于东亚部分陆地、塔里木盆地、浑善达克沙地,但该区日变化幅度在所研究几个区中最大,2000年年平均日较差达28.05 K.文中将研究时段扩充到1998～2000年后揭示了连续三年地表温度及其日变化的年际变化特征.所获得这几类地表温度的变化特征与量值对于气候与辐射收支研究以及推测地表状况会有一定参考价值. 相似文献