Soil Moisture Active Passive (SMAP) Mission

The SMAP mission objective is to provide global measurements of soil moisture and its freeze-thaw state. SMAP measures the amount of water in the top 5 cm (2 inches) of soil everywhere on the Earth’s surface every three days. These data are useful for:Further understanding of processes that link the water, energy, and carbon cyclesEnhance weather and climate prediction modelsQuantify net carbon flux in boreal landscapesDevelop improved flood-prediction and drought-monitoring capabilities The SMAP spacecraft instrumentation features an L-band radiometer and L-band synthetic aperture radar (SAR), measuring surface emissions and backscatter and sensing soil conditions through moderate vegetation cover. Level-1 SAR data products from the SMAP mission are available through the Alaska Satellite Facility DAAC. Level-1 through Level-4 radiometer data and Level-2 and Level-3 radar data are available from the National Snow and Ice Data Center DAAC. In 2015, a failure of the radar power supply caused the SAR sensor to stop operating. Therefore, active SAR data are only available for April 13 – July 7, 2015. More information on the anomaly is available from JPL. SMAP Synthetic Aperture Radar OverviewDataset PropertyValueTemporal CoverageApril 13 – July 7, 2015Repeat Cycle3 days at the equator and 2 days at boreal latitudes (>45 degrees N).Spatial CoverageWorldwideCenter FrequencyL-Band (1.2 to 1.3 GHz)Spatial Resolution• 1-3 km over the outer 70% of the swath (L1C_S0_HiRes product)• Approximately 5 km x 30 km (L1B_S0_LoRes product)Swath Width1,000 kmPolarizationsVV, HH, HVFile formatHDF5ProviderNASA Jet Propulsion Laboratory (JPL)LicenseSee License and Data Citation tabDownload infoData DiscoveryDate published:April 2015

{'The SMAP mission objective is to provide global measurements of soil moisture and its freeze-thaw state.': 'SMAP任务旨在提供全球土壤水分及其冻融状态的全面测量。', 'SMAP measures the amount of water in the top 5 cm (2 inches) of soil everywhere on the Earth’s surface every three days.': 'SMAP每三天对地球表面各处土壤表层前5厘米（2英寸）内的水分含量进行测量。', 'These data are useful for:Further understanding of processes that link the water, energy, and carbon cyclesEnhance weather and climate prediction modelsQuantify net carbon flux in boreal landscapesDevelop improved flood-prediction and drought-monitoring capabilities': '这些数据有助于：深化对水、能量和碳循环之间相互关联过程的理解，提升天气预报和气候预测模型，量化北方地区的净碳通量，以及开发更精准的洪水预测和干旱监测能力。', 'The SMAP spacecraft instrumentation features an L-band radiometer and L-band synthetic aperture radar (SAR), measuring surface emissions and backscatter and sensing soil conditions through moderate vegetation cover.': 'SMAP航天器配备L波段辐射计和L波段合成孔径雷达（SAR），能够测量地表辐射和回波，并通过中等植被覆盖感知土壤状况。', 'Level-1 SAR data products from the SMAP mission are available through the Alaska Satellite Facility DAAC. Level-1 through Level-4 radiometer data and Level-2 and Level-3 radar data are available from the National Snow and Ice Data Center DAAC.': 'SMAP任务的一级SAR数据产品可通过阿拉斯加卫星设施数据档案中心获取。一级至四级辐射计数据和二级至三级雷达数据可从国家冰雪数据中心数据档案中心获取。', 'In 2015, a failure of the radar power supply caused the SAR sensor to stop operating. Therefore, active SAR data are only available for April 13 – July 7, 2015. More information on the anomaly is available from JPL.': '2015年，雷达电源故障导致SAR传感器停止工作。因此，只有2015年4月13日至7月7日的主动SAR数据可用。关于这一异常的更多信息可从喷气推进实验室获取。', 'SMAP Synthetic Aperture Radar OverviewDataset PropertyValueTemporal CoverageApril 13 – July 7, 2015Repeat Cycle3 days at the equator and 2 days at boreal latitudes (>45 degrees N).Spatial CoverageWorldwideCenter FrequencyL-Band (1.2 to 1.3 GHz)Spatial Resolution• 1-3 km over the outer 70% of the swath (L1C_S0_HiRes product)• Approximately 5 km x 30 km (L1B_S0_LoRes product)Swath Width1,000 kmPolarizationsVV, HH, HVFile formatHDF5ProviderNASA Jet Propulsion Laboratory (JPL)LicenseSee License and Data Citation tabDownload infoData DiscoveryDate published:April 2015': 'SMAP合成孔径雷达概述
数据集属性

时间范围：2015年4月13日至7月7日
重复周期：赤道地区3天，北极地区（>45度N）2天
空间范围：全球
中心频率：L波段（1.2至1.3 GHz）
空间分辨率：
• 外部70%范围1-3公里（L1C_S0_HiRes产品）
• 大约5公里x 30公里（L1B_S0_LoRes产品）
扫描宽度：1,000公里
极化方式：VV，HH，HV
文件格式：HDF5
提供方：NASA喷气推进实验室（JPL）
许可证：见许可证和数据引用标签
下载信息
数据发现
发布日期：2015年4月'}