资源简介

摘要： 利用藏北高原那曲地区反照率地面观测资料分析了其日内、月均和季节变化特点,在此基础上,与同期的MODIS/Terra 反演结果进行了对比分析。结果表明:藏北那曲地区晴天地表反照率日内变化明显,主要表现为早晚高,变幅大,中午低,变幅小的“U”形变化特点。早晨太阳高度角低,反照率高,日内随着太阳高度角的增加反照率逐渐降低,下午14:00~15:00反照率达到日内最小值,之后随着太阳高度角的降低,反照率上升明显。夏季日内最高反照率出现在早晨8:00,其他季节则基本上在下午18:00。太阳高度角同样是影响地表反照率季节性变化的主要原因,两者呈极显著的反相关关系,相关系数为-0.91。冬季平均地表反照率最高,为0.28,其次是春秋两季,均为0.23,夏季最低,为0.19。MODIS/Terra 在上午12:00左右过境时反演的地表反照率与地面观测值之间存在很好的一致性,两者平均值都为0.22,相对误差9.60%,绝对误差和均方根误差(RMSE)均为0.02,而在13:00左右过境时,卫星反演值较观测值存在系统性偏小特点,平均偏小14.29%,相对误差为16.45%,绝对误差0.04,均方根误差0.05。此外,MODIS反演的地表反照率比地面观测值日际波动大。若不考虑积雪,冬夏两季地表反照率的空间差异小,而春秋两季空间差异较大,这主要与研究区地面植被类型及其季节性空间分布特征有关。 关键词： 地表反照率;  地面观测;  MODIS;  藏北那曲     Abstract: Land surface albedo,defined as the fraction of incident solar radiation reflected in all directions by the land surface,is one of the most important parameters controlling the climate change.Albedo directly determines the amount of solar energy absorbed by the ground,and hence,the amount of energy is available for heating the ground and lower atmosphere and evaporating water.The study on albedo changes through space and time is crucial to understand the global radiation balance and its influence on climate and vegetation dynamics.In this study,the intra\|daily,daily,monthly and seasonal variation of land surface albedo in the North Tibetan Plateau is analyzed using the ground observation data and then compared with MODIS derived albedo using narrowband to broadband conversion algorithms of land surface albedo developed by Liang.The results show that the intra\|daily changes of albedo in the North Tibetan Plateau is obvious,which indicated that it is high at mooring and afternoon with a larger range of changes,and low at noontime with a smaller range of changes ,which is characterized by “U” type.There is a statistically significant negative relationship between the observing albedo and the Solar Elevation Angle (SEA) with a correlation coefficient of -0.91,which implys SEA is main factor affecting seasonal changes of albedo.The albedo is deceasing with increase in SEA from morning to noontime,and the lowest value of albedo occurs in 14:00 to 15:00,then,albedo is increasing with decrease in SEA from noontime to afternoon.The highest albedo occurs at 8:00 of the morning in summer and at 18:00 of afternoon in other seasons.At seasonally,the highest albedo is in winter with 0.28,followed by spring and fall with 0.23,and the lowest averaged albedo is 0.19 in summer.The albeo derived from MODIS is very consistent with from ground observations at around 12:00 MODIS crossing time.However,at about 13:00 MODIS crossing time,MODIS derived albedo is systematically lower than observation data with lower than 14.29% on average.Compared to the ground observation data,the inter\|daily albedo from MODIS is more fluctuant and less smooth.

相关资源

1. 水质遥感监测的关键要素叶绿素a的反演算法研究进展
2. 基于无人机遥感技术的森林参数获取研究进展
3. 基于无线传感器网络的森林生态系统观测试验平台构建
4. 基于无人机激光雷达的森林冠层高度分析
5. 多源时序国产卫星影像的森林火灾动态监测
6. 基于无人机遥感技术的台风灾害倒伏绿化树木检测

下载说明

·如果您发现该资源不能下载，请通知管理员.gissky@gmail.com

·为确保下载的资源能正常使用，请使用[WinRAR v3.8]或以上版本解压本站资源,缺省解压密码www.gissky.net ，如果是压缩文件为分卷多文件，请依次下载每一个文件，并按照顺序命名为1.rar,2.rar,3.rar...，然后鼠标右击1.rar解压.

·为了保证您快速的下载速度，我们推荐您使用[网际快车]等专业工具下载.

·站内提供的资源纯属学习交流之用,如侵犯您的版权请与我们联系.