GEE下载降雨数据集

验中需要获取降雨数据集，需要对降水数据进行分析，故采用GEE下载此数据，亲测可以下载

1. 逐日数据分析和获取

var geometry = ee.FeatureCollection('users/www1573979951/luyixian');
Map.centerObject(geometry,7);
var dataset = ee.ImageCollection('UCSB-CHG/CHIRPS/DAILY')
.filterDate('2020-05-01', '2020-05-31')
.filterBounds(geometry)
.select('precipitation');
print(ui.Chart.image.series(dataset, geometry, ee.Reducer.mean(), 1000));
function exportImageCollection(imgCol) {
  var indexList = imgCol.reduceColumns(ee.Reducer.toList(), ["system:index"]).get("list");
  indexList.evaluate(function(indexs) {
    for (var i=0; i<indexs.length; i++) {
      var image = imgCol.filter(ee.Filter.eq("system:index", indexs[i])).first();
      image = image.clip(geometry);
      //tif数据下载
      Export.image.toDrive({
        image: image,
        description: 'pre_'+indexs[i],
        fileNamePrefix: 'pre_'+indexs[i],
        folder: 'pre',
        region: geometry,
        scale: 1000,
        crs: "EPSG:4326",
        maxPixels: 1e13
      });
    }
  });
}
exportImageCollection(dataset);

首先导入矢量范围压缩包，其次要点击矢量数据说明页，点击数据路径具体位置，复制过来：

2.逐月降雨数据下载

var geometry = ee.FeatureCollection('users/www1573979951/luyixian');
var dataset = ee.ImageCollection('UCSB-CHG/CHIRPS/DAILY').filterBounds(geometry).select('precipitation');
//时间范围
var years = ee.List.sequence(2020, 2020);
var months = ee.List.sequence(1, 12);

//将逐日数据生成月平均数据
var monthlysum =  ee.ImageCollection.fromImages(
  years.map(function (y) {
    return months.map(function(m) {
      return dataset.filter(ee.Filter.calendarRange(y,y, 'year'))
      .filter(ee.Filter.calendarRange(m, m, 'month'))
      .sum().set('year', y).set('month', m).set('system:time_start', ee.Date.fromYMD(y, m, 1));
    });
  }).flatten());

print(monthlysum);
print(ui.Chart.image.series(monthlysum, geometry, ee.Reducer.mean(), 1000));

function exportImageCollection(imgCol) {
  var indexList = imgCol.reduceColumns(ee.Reducer.toList(), ["system:index"]).get("list");
  indexList.evaluate(function(indexs) {
    for (var i=0; i<indexs.length; i++) {
      var image = imgCol.filter(ee.Filter.eq("system:index", indexs[i])).first();
      image = image.clip(geometry);
      //tif数据下载
      Export.image.toDrive({
        image: image,
        description: 'pre_2020_'+indexs[i],
        fileNamePrefix: 'pre_2020_'+indexs[i],
        folder: 'pre',
        region: geometry,
        scale: 1000,
        crs: "EPSG:4326",
        maxPixels: 1e13
      });
    }
  });
}
exportImageCollection(monthlysum);

3.逐年降雨数据下载：

var geometry = ee.FeatureCollection('users/www1573979951/luyixian');
// 选择数据集并进行波段比例换算
var collection = ee.ImageCollection("UCSB-CHG/CHIRPS/DAILY").filterDate('2000-01-01', '2020-12-31').select("precipitation");

//进行年平均值的计算
var years = ee.List.sequence(2000, 2020);
var collectYear = ee.ImageCollection(years
  .map(function(y) {
    var start = ee.Date.fromYMD(y, 1, 1);
    var end = start.advance(12, 'month');
    return collection.filterDate(start, end).reduce(ee.Reducer.sum()).float().set('system:time_start',y).set('year',y);
}));
print(collectYear);
//年均值的时间序列展示
var Yearly_chart = ui.Chart.image.series({
    imageCollection: collectYear.select('precipitation_sum'),
    region: geometry,
    reducer: ee.Reducer.mean(),
    scale: 500,
    xProperty: 'year',
    }).setOptions({
      interpolateNulls: true,
      lineWidth: 2,
      title: 'pre Yearly Seires',
      vAxis: {title: 'pre'},
      hAxis: {title: 'Date'},
    });
print(Yearly_chart);

function exportImageCollection(imgCol) {
  var indexList = imgCol.reduceColumns(ee.Reducer.toList(), ["system:index"]).get("list");
  indexList.evaluate(function(indexs) {
    for (var i=0; i<indexs.length; i++) {
      var image = imgCol.filter(ee.Filter.eq("system:index", indexs[i])).first();
      image = image.clip(geometry);
      //tif数据下载
      Export.image.toDrive({
        image: image,
        description: 'pre_'+indexs[i],
        fileNamePrefix: 'pre_'+indexs[i],
        folder: 'pre',
        region: geometry,
        scale: 1000,
        crs: "EPSG:4326",
        maxPixels: 1e13
      });
    }
  });
}
exportImageCollection(collectYear);