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首页> 外文学位 >Determination of MODIS thermal response patterns from land surfaces and their relationship with climatic factors for drought monitoring in central Great Plains.
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Determination of MODIS thermal response patterns from land surfaces and their relationship with climatic factors for drought monitoring in central Great Plains.

机译：确定大平原中部MODIS地面热响应模式及其与气候因子的关系，以进行干旱监测。

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摘要

Daily land surface temperatures (LST) derived from Moderate Resolution Imaging Spectroradiometer (MODIS) data were analyzed to determine how the data were correlated with climatic water balance variables and NDVI anomalies during a growing season 2000 in western and central Kansas. Based on surface energy balance climatology, LST should respond to drying conditions well before plant response. To test this hypothesis, four daily water budget factors, percent soil moisture (SM), actual/potential evapotranspiration ratio (AE/PE), moisture deficit (MD), and moisture deficit/potential evapotranspiration ratio (MD/PE), were calculated. These variables were expected to have significant correlations with LST deviation from air temperature.; To perform correlation analyses on a weekly basis, daily MODIS data were integrated into three different types of weekly composites, including aggregations based on maximum observed LST, the driest day since last rainfall, and a combination of maximum temperature and the driest day. Results showed that the maximum-temperature composite had the highest, and the driest-day composite had the lowest, correlation with the climatic water budget parameters. Time-integrated, or cumulative values of the LST deviation showed even stronger relationships with the water budget factors, increasing the correlation coefficients by 33.4% on average.; To rescale the temperature signals from 0 to 1, the Standardized Thermal Index (STI) is proposed in this study. The STI, based on cumulative surface temperatures standardized with observed mean air temperatures, had significant temporal relationships with the hydroclimatological factors. STI classes in all the composite periods also had a strong correlation with NDVI declines during the drought episode. Results showed that, based on LST, air temperature observations, and water budget analysis, NDVI declines below a normal could be predicted as early as 8 weeks in advance in this study area.; Finally, the STASTGO database was used within a GIS environment to determine the influences of hydrologic soil properties on soil moisture and thermal emission. Two important variables, water-holding capacity (WHC) and hydrologic soil group (HSG), were evaluated in water budget experiments to determine their impacts on changes in soil moisture content (SMC). Results showed that HSG affected SMC changes very little, but that WHC variations explained most local variations of SMC. As a strong indicator of relative soil moisture deficit (MD/PE), the Standardized Thermal Index (STI) patterns were also influenced by WHC. Generally, the earlier SMC drops below WHC 40%, the earlier the STI reached the threshold value of 0.2.
机译：分析了中分辨率成像光谱仪（MODIS）数据得出的每日地表温度（LST），以确定该数据如何与2000年西部和中部堪萨斯州生长季节的气候水平衡变量和NDVI异常相关。基于表面能平衡气候，LST应该在植物响应之前就对干燥条件做出响应。为了检验该假设，计算了四个每日水预算因子，土壤湿度百分比（SM），实际/潜在蒸散率（AE / PE），水分亏缺（MD）和水分亏缺/潜在蒸散率（MD / PE）。 。预计这些变量与LST与气温的偏差具有显着的相关性。为了每周进行相关分析，将每日MODIS数据集成到三种不同类型的每周组合中，包括基于最大观测到的LST，自上次降雨以来最干旱的一天以及最高温度和最干旱的一天的组合的汇总。结果表明，最高温度综合指数最高，而最干燥日综合指数最低，与气候水预算参数相关。 LST偏差的时间积分值或累积值显示出与水预算因素的更强关系，平均相关系数提高了33.4％。为了将温度信号从0缩放到1，本研究提出了标准热指数（STI）。 STI基于累积的表面温度和观测的平均气温标准化，与水文气候因素具有明显的时间关系。在所有复合时期，STI类与干旱期间NDVI的下降也有很强的相关性。结果表明，基于LST，空气温度观测和水预算分析，可以预测该研究区域的NDVI最早可提前8周降到正常水平以下。最后，在GIS环境中使用STASTGO数据库来确定水文土壤性质对土壤水分和热量排放的影响。在水预算实验中评估了两个重要变量，持水量（WHC）和水文土壤组（HSG），以确定它们对土壤含水量（SMC）变化的影响。结果表明，HSG对SMC的影响很小，但是WHC的变化解释了SMC的大多数局部变化。作为相对土壤水分亏缺（MD / PE）的有力指标，标准热指数（STI）模式也受到WHC的影响。通常，SMC越早下降到WHC 40％以下，STI越早达到阈值0.2。

著录项

  • 作者

    Park, Sunyurp.;

  • 作者单位

    University of Kansas.;

  • 授予单位 University of Kansas.;
  • 学科 Physical Geography.; Environmental Sciences.
  • 学位 Ph.D.
  • 年度 2003
  • 页码 171 p.
  • 总页数 171
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 自然地理学;环境科学基础理论;
  • 关键词

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