GLDAS Precipitation 2000 - Present

Precipitation is water released from clouds in the form of rain, sleet, snow, or hail. It is the primary source of recharge to the planet's fresh water supplies. This map contains a historical record showing the volume of precipitation that fell during each month from March 2000 to the present. Snow and hail are reported in terms of snow water equivalent - the amount of water that will be produced when they melt. Dataset Summary The GLDAS Precipitation layer is a time-enabled image service that shows average monthly precipitation from 2000 to the present, measured in millimeters. It is calculated by NASA using the Noah land surface model, run at 0.25 degree spatial resolution using satellite and ground-based observational data from the Global Land Data Assimilation System (GLDAS-2.1). The model is run with 3-hourly time steps and aggregated into monthly averages. Review the complete list of model inputs, explore the output data (in GRIB format), and see the full Hydrology Catalog for all related data and information! Phenomenon Mapped: Precipitation Units: Millimeters Time Interval: Monthly Time Extent: 2000/01/01 to present Cell Size: 28 km Source Type: Scientific Pixel Type: Signed Integer Data Projection: GCS WGS84 Mosaic Projection: Web Mercator Auxiliary Sphere Extent: Global Land Surface Source: NASA Update Cycle: Sporadic What can you do with this layer? This layer is suitable for both visualization and analysis. It can be used in ArcGIS Online in web maps and applications and can be used in ArcGIS for Desktop. It is useful for scientific modeling, but only at global scales. By applying the "Calculate Anomaly" processing template, it is also possible to view these data in terms of deviation from the mean. Mean precipitation for a given month is calculated over the entire period of record - 2000 to present. Time: This is a time-enabled layer. By default, it will show the first month from the map's time extent. Or, if time animation is disabled, a time range can be set using the layer's multidimensional settings. If you wish to calculate the average, sum, or min/max over the time extent, change the mosaic operator used to resolve overlapping pixels. In ArcGIS Online, you do this in the "Image Display Order" tab. In ArcGIS Pro, use the "Data" ribbon. In ArcMap, it is in the 'Mosaic' tab of the layer properties window. If you do this, make sure to also select a specific variable. The minimum time extent is one month, and the maximum is 8 years. Variables: This layer has three variables: total precipitation, rainfall and snowfall. By default total is shown, but you can select a different variable using the multidimensional filter, or by applying the relevant raster function. Important: You must switch from the cartographic renderer to the analytic renderer in the processing template tab in the layer properties window before using this layer as an input to geoprocessing tool.降水是指以雨、雨夹雪、雪或冰雹形式从云层降落的水，是地球淡水补给的主要来源。本数据集包含2000年3月至今各月的降水总量历史记录。其中雪与冰雹以雪水当量（snow water equivalent）进行统计，即其融化后产生的液态水总量。 数据集摘要 GLDAS降水图层是一项支持时间维度的影像服务，展示了2000年至今的月均降水量，单位为毫米。该数据集由美国国家航空航天局（NASA）采用Noah陆面模型计算生成，空间分辨率为0.25度，所用数据源自全球陆面数据同化系统（GLDAS-2.1）的卫星与地面观测资料。模型以3小时间隔运行，最终聚合为月均数据。可查阅完整的模型输入参数列表，探索GRIB格式的输出数据，或访问完整的水文学目录以获取所有相关数据与信息！ 制图映射要素： 降水 单位：毫米 时间间隔：月度 时间范围：2000/01/01 至今 像元尺寸：28千米 源数据类型：科学数据 像元类型：有符号整数 数据投影：GCS WGS84 镶嵌投影：Web Mercator辅助球面 覆盖范围：全球陆面 数据来源：NASA 更新周期：不定期 图层用途 本图层适用于可视化与分析工作，可在ArcGIS Online的网络地图与应用中调用，也可在ArcGIS for Desktop中使用。其可用于科学建模，但仅支持全球尺度的分析。通过应用「计算距平」处理模板，还可将数据以距平值形式展示，即相对于多年均值的偏差。指定月份的多年均值基于2000年至今的完整记录期计算得到。 时间维度说明 本图层支持时间维度功能。默认情况下将显示地图时间范围内的首个月份；若禁用时间动画，则可通过图层的多维设置自定义时间范围。若需计算时间范围内的平均值、总和或最值，请更改用于解决像元重叠问题的镶嵌运算符：在ArcGIS Online中，可在「影像显示顺序」标签页中完成设置；在ArcGIS Pro中，需通过「数据」选项卡操作；在ArcMap中，则需在图层属性窗口的「镶嵌」标签页中配置。进行此类操作时，请务必同时选择特定的变量。时间范围的最小跨度为1个月，最大跨度为8年。 变量说明 本图层包含三个变量：总降水量、降雨量与降雪量。默认显示总降水量，您可通过多维过滤器或应用相关栅格函数选择其他变量。 重要提示 在将本图层作为地理处理工具的输入之前，请务必在图层属性窗口的处理模板标签页中，将制图渲染器切换为分析渲染器。