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Etude de la variabilite climatique des hautes latitudes nord, derivee d'observations satellites micro-ondes.

机译:根据微波卫星观测结果对北高纬度地区的气候变化进行研究。

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摘要

Observing sub-polar ecosystems is important as they are suspected to change significantly in response to the expected increase in temperature for the next decades. To bypass the lack of meteorological stations in the Northern High Latitudes, remote sensing is an interesting alternative tool, covering almost the entire area. This project deals with the development of a method to derive surface parameters (>50°N) from satellite data. For this study, brightness temperature data acquired by the SSM/I (Special Sensor Microwave Imager) in the microwave spectrum are used because they are independent of solar radiation and weakly influenced by the atmosphere. Methods used are based on brightness temperatures measured at 19 and 37 GHz, which allow to derive three geophysical parameters related to climate variability: daily maps of snowcover between 1988 and 2002; a water surface extent (open water, small lakes, reservoirs, wetlands associated with low vegetation); a temperature characterizing the surface and the air above the ground. A method to normalize the temperature is presented to overcome the variation of the time of measurement. It leads to hourly series of temperature, This allows to study climate indicators such as the annual sum of positive degree days. Trends confirm observed climate evolution: increase of surface temperature (+0.8 +/- 0.4°C for Canada/Alaska between 1992 and 2002), decrease in snow extent cover. These original databases could also be useful for validation of regional climate model. (Abstract shortened by UMI.)
机译:观测亚极生态系统非常重要,因为怀疑它们会随着未来几十年温度的预期升高而发生显着变化。为了绕过北部高纬度地区缺少气象站的情况,遥感是一种有趣的替代工具,几乎涵盖了整个区域。该项目致力于从卫星数据中得出地表参数(> 50°N)的方法的开发。在本研究中,使用了由SSM / I(特殊传感器微波成像仪)在微波频谱中获取的亮度温度数据,因为它们与太阳辐射无关并且受大气的影响很小。所使用的方法基于在19 GHz和37 GHz下测得的亮度温度,这可以得出与气候多变性相关的三个地球物理参数:1988年至2002年的积雪日图;水面范围(开放水域,小湖,水库,与低植被有关的湿地);表征地面和地面上方空气的温度。提出了一种标准化温度的方法,以克服测量时间的变化。它导致每小时的温度序列,从而可以研究气候指标,例如,每年的正度天数之和。趋势证实了观察到的气候演变:地表温度升高(1992年至2002年之间,加拿大/阿拉斯加为+0.8 +/- 0.4°C),降雪量减少。这些原始数据库也可用于验证区域气候模型。 (摘要由UMI缩短。)

著录项

  • 作者

    Mialon, Arnaud.;

  • 作者单位

    Universite de Sherbrooke (Canada).;

  • 授予单位 Universite de Sherbrooke (Canada).;
  • 学科 Geotechnology.; Physics Atmospheric Science.; Remote Sensing.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 229 p.
  • 总页数 229
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 地质学;大气科学(气象学);遥感技术;
  • 关键词

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