GLDAS Soil Moisture 2000 - Present

Soils and soil moisture greatly influence the water cycle and have impacts on runoff, flooding and agriculture. Soil type and soil particle composition (sand, clay, silt) affect soil moisture and the ability of the soil to retain water. Soil moisture is also affected by levels of evaporation and plant transpiration, potentially leading to near dryness and eventual drought. Measuring and monitoring soil moisture can ensure the fitness of your crops and help predict or prepare for flash floods and drought. The GLDAS soil moisture data is useful for modeling these scenarios and others, but only at global scales. Dataset Summary The GLDAS Soil Moisture layer is a time-enabled image service that shows average monthly soil moisture from 2000 to the present, measured as the millimeters of water contained within four different depth levels. 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: Soil Moisture 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 Desktop. The GLDAS soil moisture data is useful for 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 soil moisture 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 five variables, corresponding to different depth levels. By default total is shown, but you can view an individual depth level 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 tools.土壤及其含水量对水循环具有显著影响，并会作用于径流、洪涝与农业生产。土壤类型与土壤颗粒组成（砂粒、黏粒、粉粒）会影响土壤含水量及其持水能力。土壤含水量同时受蒸发与植物蒸腾强度的影响，可能引发土壤近干状态，最终导致干旱。对土壤含水量进行测量与监测，可保障作物生长健康，并助力提前预警或应对山洪与干旱灾害。全球陆面数据同化系统（Global Land Data Assimilation System, GLDAS）土壤湿度数据可用于模拟上述及其他场景，但仅适用于全球尺度的分析。 数据集概览 GLDAS土壤湿度图层为启用时间功能的影像服务，展示了2000年至今的逐月平均土壤含水量，以四种不同深度土层内的含水毫米数为计量单位。该数据集由美国国家航空航天局（National Aeronautics and Space Administration, NASA）基于Noah陆面模式计算生成，空间分辨率为0.25度，所用数据来源于全球陆面数据同化系统2.1版本（GLDAS-2.1）的卫星与地面观测资料。模式以3小时为时间步长运行，并聚合为逐月平均值。可查阅完整的模式输入参数列表、获取GRIB格式的输出数据，以及通过完整的水文目录查看所有相关数据与信息！ 制图现象：土壤含水量 单位：毫米 时间间隔：逐月 时间范围：2000年1月1日至今 像元大小：28千米 数据源类型：科学数据 像素类型：有符号整数 数据投影：GCS WGS84 镶嵌投影：Web Mercator辅助球体 覆盖范围：全球陆面 数据来源：美国国家航空航天局（NASA） 更新周期：不定期 该图层可应用于以下场景： 本图层兼具可视化与分析功能，可在ArcGIS Online的网页地图与应用中使用，也可适配ArcGIS Desktop软件。GLDAS土壤湿度数据仅适用于全球尺度的模拟分析。通过应用「计算距平」处理模板，还可将数据以距平（即与平均值的偏差）形式展示。指定月份的平均土壤含水量以2000年至今的完整记录周期计算得出。 时间属性说明： 本图层为启用时间功能的图层。默认情况下，将显示地图时间范围内的首个月份数据；若关闭时间动画功能，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、总和或最大/最小值，请修改用于处理重叠像元的镶嵌运算符。在ArcGIS Online中，可通过「影像显示顺序」选项卡进行设置；在ArcGIS Pro中，需通过「数据」功能区操作；在ArcMap中，则需在图层属性窗口的「镶嵌」选项卡中完成。执行此操作前，请务必先选择特定的变量。时间范围的最小跨度为1个月，最大跨度为8年。 变量说明： 本图层包含五个变量，分别对应不同的土层深度。默认显示总含水量，您也可通过多维过滤器或应用对应的栅格函数查看单一层级的土壤含水量。 重要提示： 若需将本图层作为地理处理工具的输入数据，请先在图层属性窗口的「处理模板」选项卡中，将渲染器从制图渲染器切换为分析渲染器。