caliop 数据可视化

caliop 数据可视化

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摘 要

云对地球的环境和气候有着很大的影响，云的辐射特性和高度影响到太阳辐射收支，从而导致地球变暖或变冷。为了精确描述能量收支，对云的微物理性质(如云形态和云粒直径)和简单的几何性质(如云顶高度)的研究是必不可少的。

MODIS获取了高时间频次、全球覆盖的云产品数据，为了解该云产品的数据质量，以CALIPSO数据为基准，分析了MODIS云顶高度产品的准确性以及误差产生的原因。

主要工作及成果如下：

数据获取及处理。选择时间、地点对应的低、中、高纬度地区的CALIPSO和MODIS云高产品数据。

对MODIS云高产品数据进行几何纠正，并根据C ALIPSO经纬度数据找到MODIS数据对应区域。

数据对比与分析。把同一时空下的两种数据做差值运算，并求取差值的平均值和标准差。包括不同纬度、不同高度、不同云层数的云顶高度对比与分析。

MODIS云顶高度误差的空间分布分析。通过对比CALIPSO和MODIS云顶高度，发现在低纬度地区，MODIS云顶高度产品误差较大；在中纬度和极地地区，误差较小；对于大于5KM的云，误差较大；小于5KM的云，误差较小；对于单层云，误差较小，对于多层云，误差较大。

关键词：CALIPSO；MODIS；云顶高度

ABSTRACT

Cloud has a large impact on the Earth's environment and climate.Their impact on the radiation budget can result in a heating or a cooling of the planet, depending on the radiative properties of a cloud and its altitude. In order to describe the energy budget accurately, the study of the microphysical properties (such as cloud morphology and cloud particle diameter) and simple geometric properties (such as cloud top height) of the clouds is essential.

MODIS obtains the data of the cloud products with the high frequency and the global coverage. Based on the CALIPSO data, the accuracy and the cause of the error are analyzed of the cloud top height products which produced by MODIS, in order to understand the data quality of the cloud products.

The main work and achievements are as follows:

(1) Data acquisition and processing. Select the low, medium and high latitudes of the CALIPSO and MODIS cloud high product data, which has the same time and location.

(2) Doing geometric correction to MODIS cloud top height product data, and finding MODIS data corresponding region according to CALIPSO latitude and longitude data.

(3) Data comparison and analysis. Doing the difference calculation of the two kinds of data which has same time and space, and calculate the differences’ average and standard deviation. Including different latitude, different height, different cloud layers of cloud top height contrast and analysis.

(4) Spatial distributio