一种自动土壤水分数据质量控制预警方法

Data Quality Early Warning of Automatic Soil Water Observations Based on Soil Hydrological Constants

根据实时业务中传输的自动土壤水分监测数据的变化规律,对监测数据异常波动产生的异常值进行预警;通过观测值间相互关系推算相应的土壤水分常数,近似确定土壤孔隙度、最大吸湿水含量,以此确定土壤水分理论上下限并据此开展监测值的上下限预警;参考土壤含水量与水势之间的变化关系,提出水势系数的概念,直接利用计算的水势系数进行土壤水分层间变化的预警等3方面对自动土壤水分监测数据进行质控预警,并针对业务应用设计了相应的预警方案,可实时、有效地检测出异常值。从该预警方案的预警效果分析上看,预警检出率较高主要是"常数预警"和"数值变化预警",反映出小部分自动土壤水分观测站的土壤水分常数异常和部分站点业务运行维护不到位,这与野外实地考察的结论相吻合。预警效果较为客观、可靠,适用于各级土壤水分数据检测和分析服务等业务。

Three strategies on data quality early warning of automatic soil water observations are setup：（1）Abnormal value detection of the automatic soil observation data is conducted based on the regularity of the soil moisture evolution.（2）From the relationship between soil observations,the soil hydrological constants are calculated,which are used to determine the theoretically soil moisture boundary for the automatic soil observation data limit tests.（3）Referring to the relationships between soil water content and soil water flow trend,the water potential flow trend coefficient is set up by using the real water contents as well as its field capacity and wilting moisture,which is used to analyze the unreasonable distributions of soil water among the different soil layers.Based on the data of early warning strategies,the operatiing scheme is setup for data quality check in real time.The outputs from the early warning system shows that the relative higher detection rate implies to the suspicious soil hydrological constants,which is used in calculating the soil moisture from the instrument signals,and the inappropriate observation environment of the instrument due to the soil hole,cracks,and so on around the instrument after installation.The warning results are consistent with the conclusions from the automatic soil water observation station field investigations.The warning effects are objective,reliable,and suitable for different levels of operation sectors to use automatic soil water data in routine services.