黑河生态水文遥感试验：黑河流域上游PLMR地面同步观测数据集（2012年8月1日）

2012年8月1日在黑河上游加密观测区东支、阿柔和西支，开展了样带、样方机载PLMR飞行地面同步观测。PLMR（Polarimetric L-band Multibeam Radiometer）是双极化（H/V）的L波段微波辐射计，中心频率1.413 GHz，带宽24 MHz，分辨率1 km （相对航高3 km），有6个beam同时观测，入射角为±7º，±21.5º，±38.5º，灵敏度<1K。飞行主要覆盖中游人工绿洲生态水文试验区。本地面同步数据集可为发展和验证被动微波遥感反演土壤水分算法提供基本地面数据集。
样方及采样策略：
观测区涉及范围较大，因此在八宝河东支和西支均采用一条样带观测，观测点间隔50 m，采样中考虑到距离过长，为保证与飞行观测尽量同步，每隔一定距离开展观测。在阿柔草场设置2个样方，分别为1.5 km×0.6 km 和0.85 km×0.6 km，在这两个样方上采样点南北间隔100 m，东西间隔50 m。
使用4台Hydraprobe Data Acquisition System （HDAS，参考文献2）和3台POGO便携式土壤传感器同时测量。
测量内容：
观测获得土壤温度、土壤水分（体积含水量）、损耗正切、土壤电导率、土壤复介电实部及虚部。植被参数观测选择在一些具有代表性的土壤水分采样点开展，完成了覆盖度、株高和生物量（植被含水量）的测量。
数据：
本数据集包括土壤水分观测和植被观测两部分，前者保存数据格式为矢量文件，空间位置即为各采样点位置（WGS84+UTM 47N），土壤水分等测量信息记录在属性文件中；植被采样信息记录在EXCEL表格中。

On August 1, 2012, synchronous ground-based observations were carried out along transects and plots during an airborne PLMR (Polarimetric L-band Multibeam Radiometer) flight over the East Branch, Arou, and West Branch of the intensive observation area in the upper reaches of the Heihe River. PLMR is a dual-polarization (H/V) L-band microwave radiometer with a center frequency of 1.413 GHz, bandwidth of 24 MHz, spatial resolution of 1 km (at a relative flight altitude of 3 km), capable of simultaneous observations with 6 beams at incidence angles of ±7º, ±21.5º, and ±38.5º, and a radiometric sensitivity of less than 1 K. The flight mainly covered the middle reaches artificial oasis eco-hydrological experimental area. This ground synchronous dataset can provide fundamental ground reference data for developing and validating passive microwave remote sensing soil moisture retrieval algorithms.

Plot and Sampling Strategy:
Given the large scope of the observation area, a transect survey was implemented for both the East and West Branches of the Babao River, with an observation point interval of 50 m. Considering the long distance of the transect, observations were arranged at fixed intervals to ensure maximum synchronization with the airborne flight. Two plots were set up in the Arou Grassland, with sizes of 1.5 km×0.6 km and 0.85 km×0.6 km respectively. Within these two plots, sampling points were spaced 100 m apart in the north-south direction and 50 m apart in the east-west direction.

Four Hydraprobe Data Acquisition Systems (HDAS, Reference 2) and three POGO portable soil sensors were used for simultaneous measurements.

Measurement Contents:
Observed parameters include soil temperature, soil moisture (volumetric water content), loss tangent, soil electrical conductivity, and the real and imaginary parts of soil complex permittivity. Vegetation parameter measurements were conducted at representative soil moisture sampling points, covering vegetation coverage, plant height, and biomass (vegetation water content).

Dataset:
This dataset includes two parts: soil moisture observations and vegetation observations. The soil moisture observations are stored as vector files, where the spatial positions correspond to the locations of each sampling point (WGS84 + UTM 47N), and measurement information such as soil moisture is recorded in the attribute files. Vegetation sampling information is recorded in an Excel spreadsheet.