中国雪深长时间序列数据集（1979-2025）

该数据集是“中国雪深长时间序列数据集（1978-2012）”的升级版本。 中国雪深长时间序列数据集（1979-2025）采用经纬度投影方式，数据为浮点型。数据集按年份存储，每个年份是一个压缩包，每个压缩包内包含每天的积雪深度文件。每天的雪深用一个txt文件存储，文件的名称为“yyyyddd.txt”，其中yyyy代表年，ddd代表Julian日期，雪深单位为厘米（cm）。比如2005001.txt就代表这个ASCII文件描述2005年第一天我国的积雪覆盖状况。数据集的ASCII码文件是由头文件和主体内容构成，头文件包括行数、列数、x-轴中心点坐标、y-轴中心点坐标、栅格大小、无数据区标值等6行描述信息组成，主体内容就是根据行数列数组成的二维数组，雪深单位为厘米（cm）。因为该数据集中的所有ASCII码文件所描述的空间为我国全国范围，所以这些文件的头文件是不变的，现将头文件摘录如下（其中xllcenter, yllcenter, cellsize单位为度）： ncols 321 nrows 161 xllcenter 60 yllcenter 15 cellsize 0.25 NODATA_value -1。
该数据集是采用中国被动微波雪深反演算法Che算法，从星载被动微波亮度温度数据提取。星载被动微波亮度温度数据来自多个传感器，本数据采用的传感器包括Nimbus7上的SMMR(1979-1988),DMSP-F08,F11,F13上的SSMI（1988-2008），DMSP-F17上的SSMI/S（2009-2020），Aqua上的AMSR-E （2002-2011），GCOM-W1上的AMSR2 (2012-)。考虑到不同传感器之间的系统差异，在进行雪深反演前，已对对不同传感器进行了交叉订正。
数据包含四个压缩文件：daily snow depth _smmr_ssmis_China (1979-2020),daily snow depth _amsre_China(2002-2011),daily snow depth_amsr2_China（2012-2024）,daily snow depth_amsr2_China_full（2024-08-2025-11）。第一个是从SMMR,SSMI,SSMI/S提取的1979-2020年逐日雪深，第二个是从AMSR-E提取的2002-2011年逐日雪深，第三个是从AMSR2提取的2012-2024年逐日雪深,第四个是从AMSR2提取的2024-08-2025-11逐日雪深。从2021年开始SSMI/S数据与之前差异较大，因此，之后的数据不再根据SSMI/S数据更新。AMSR-E数据结束时间是2011年9月27日。AMSR2数据从2012年9月1日开始，目前仍在运行，今后将根据AMSR2数据继续更新中国长时间序列数据集。

This dataset is an upgraded version of the long-term time-series snow depth dataset for China (1978-2012).
The long-term time-series snow depth dataset for China (1979-2024) adopts the latitude-longitude projection, and the data is of floating-point type.
The dataset is stored by year, with each year corresponding to a compressed archive, which contains the daily snow depth files.
Daily snow depth is stored in a TXT file named "yyyyddd.txt", where yyyy represents the year and ddd represents the Julian day. The unit of snow depth is centimeter (cm). For example, 2005001.txt indicates that this ASCII file describes the snow cover status of China on the first day of 2005.

Each ASCII file of the dataset consists of a header file and a main content section. The header file contains 6 lines of descriptive information, including the number of rows, number of columns, x-axis center coordinate, y-axis center coordinate, grid cell size, and NODATA_value. The main content is a two-dimensional array arranged according to the number of rows and columns, with the unit of snow depth being centimeter (cm). Since the spatial scope described by all ASCII files in this dataset covers the entire territory of China, the header files of these files are identical. The header file is excerpted as follows (the units of xllcenter, yllcenter, and cellsize are degrees):
ncols 321
nrows 161
xllcenter 60
yllcenter 15
cellsize 0.25
NODATA_value -1

This dataset is extracted from spaceborne passive microwave brightness temperature data using the Che algorithm, a Chinese passive microwave snow depth retrieval algorithm. The spaceborne passive microwave brightness temperature data comes from multiple sensors. The sensors used in this dataset include SMMR on Nimbus-7 (1979-1988), SSMI on DMSP-F08, F11 and F13 (1988-2008), SSMI/S on DMSP-F17 (2009-2020), AMSR-E on Aqua (2002-2011), and AMSR2 on GCOM-W1 (2012-present). Considering the systematic differences between different sensors, cross-calibration has been performed for all sensors prior to snow depth retrieval.

The dataset includes three compressed archives: daily snow depth _smmr_ssmis_China (1979-2020), daily snow depth _amsre_China (2002-2011), and daily snow depth_amsr2_China (2012-2024). The first archive contains daily snow depth data from 1979 to 2020 extracted from SMMR, SSMI, and SSMI/S; the second contains daily snow depth data from 2002 to 2011 extracted from AMSR-E; and the third contains daily snow depth data from 2012 to 2024 extracted from AMSR2. Since the SSMI/S data differs significantly from earlier datasets starting in 2021, subsequent data will no longer be updated based on SSMI/S data. The AMSR-E data ceased on September 27, 2011. The AMSR2 data started on September 1, 2012, and is still in operation. The long-term time-series snow depth dataset for China will continue to be updated using AMSR2 data in the future.

AI搜集汇总

背景与挑战

背景概述

该数据集是中国积雪深度的日值长时间序列数据，覆盖1979年至2024年，空间覆盖全国范围，空间分辨率为0.25度。数据基于被动微波遥感反演，融合了多种传感器并进行了交叉订正，确保了数据的一致性和连续性，以开放获取方式共享，适用于冰冻圈和气候变化研究。