Spatiotemporal characteristics of extreme precipitation regimes in the Eastern Inland River Basin of Inner Mongolian Plateau, China

In this work, we use the gridded precipitation dataset (with a resolution of 0.5° × 0.5°) of the eastern part of inland river basin of Inner Mongolian Plateau from 1961–2015 as the basis and adopt the methods of climatic diagnosis (e.g., the Modified Mann-Kendall method, principal component analysis, and correlation analysis) to analyze the spatial and temporal variations of six extreme precipitation indices. Furthermore, we analyzed the relationship between El Niño–Southern Oscillation (ENSO) events and the observed extreme precipitation. The results indicated that the gridded dataset can be used to describe the precipitation distribution in our study area. In recent 55 years, the inter-annual variation trends of extreme precipitation indices are generally dominated by declination except for the maximum precipitation over five days (RX5DAY) and the heavy precipitation (R95P), in particular, the decreasing regions of consecutive dry days (CDD) accounts for 91% of the entire basin, 17.28% of which is showing the significant downward trend. Contrary to CDD, the spatial distribution of the other five indices is gradually decreasing from northeast to southwest, and the precipitation intensity (SDII) ranges from 3.8–5.3 mm·d−1, with relatively small spatial differences. To some extent, CDD and R95P can used to characterize the extreme precipitation regimes. Moreover, the number of days with heavy precipitation (RR10), SDII, and R95P are more susceptible to the ENSO events. In addition, the moderate El Niño event may increase the probability of CDD, while the La Niña events may increase the risk of the heavy rainfall regime in the study area

Metadata describing the Kharaa Yeröö River Basin Water Quality Database

n the framework of the BMBF funded project on Integrated Water Resources Management in Central Asia (Model region Mongolia, MOMO project, www.iwrm-momo.de) the objectives focused on supplementing, validating and extending the existing surveillance monitoring to the entire river basin for the time series 2006-2017. The MOMO monitoring programme was set up in order to observe seasonal variation in various water quality parameters along the main river course and its tributaries. A detailed sampling survey was carried out along the Kharaa River in the spring, summer and autumn of 2006 to 2017, extending from the headwaters in the Khentii Mountains to the outlet of the river basin. An additional continuous monthly monitoring programme for surface water quality was carried out upstream (Deed Guur) and downstream of Darkhan city (Buren Tolgoi) including the outlet of WWTP Darkhan in the time between 2007 and 2017. This strategy provides information for the efficient and effective design of future monitoring programmes with a focus on operational or investigative issues. The types of water sampling programmes included initial surveys as well as investigative and operational monitoring, point-source characterization, intensive surveys, fixed-station-network monitoring, groundwater monitoring, and special surveys involving chemical and biological monitoring. The water analyses have a focus on nutrients, heavy metals and metalloids, chloride, boron and the main physical water parameters. The dataset comprises also fluvial sediment analyses on heavy metals. In addition in 2017 a special hygienic monitoring (total coliforms, E. coli and fecal coliforms) has been carried out and was included in this database