Like in all ancient civilisations, the need to manage water propelled the growth of hydrological science in ancient India also. In this paper, we provide some fascinating glimpses into the hydrological, hydraulic, and related engineering knowledge that existed in ancient India, as discussed in contemporary literature and recent explorations and findings. Many interesting dimensions of early scientific endeavours emerge as we investigate deeper into ancient texts, including Indian mythology.

We focus on the net exchange of water between land and air via evapotranspiration and dew during the night. We provide, for the first time, an overview of the magnitude and variability of this flux across the globe from observations and climate models. Nocturnal water loss from land is 7 % of total evapotranspiration on average and can be greater than 15 % locally. Our results highlight the relevance of this often overlooked flux, with implications for water resources and climate studies.

This study represents the most comprehensive global-scale precipitation dataset evaluation to date. We evaluated 13 uncorrected precipitation datasets using precipitation observations from 76 086 gauges, and 9 gauge-corrected ones using hydrological modeling for 9053 catchments. Our results highlight large differences in estimation accuracy, and hence, the importance of precipitation dataset selection in both research and operational applications.

We have assimilated 6 years of satellite-observed passive microwave data into a state-of-the-art land surface model to improve surface soil moisture as well as root-zone soil moisture simulations. Long-term assimilation effects/biases are identified, and they are especially dependent on model perturbations, applied to simulate model uncertainty. The implications are put into context of using such assimilation-improved data for classifying extremes within hydrological monitoring systems.

The new SMOS satellite near-real-time (NRT) soil moisture (SM) product based on a neural network is presented. The NRT SM product has been evaluated with respect to the SMOS Level 2 product and against a large number of in situ measurements showing performances similar to those of the Level 2 product but it is available in less than 3.5 h after sensing. The new product is distributed by the European Space Agency and the European Organisation for the Exploitation of Meteorological Satellites.

Terrestrial water storage is defined as the total volume of water stored within the land surface and sub-surface and is a key variable for tracking long-term variability in the global water cycle. Currently, annual variations in terrestrial water storage can only be measured at extremely coarse spatial resolutions (> 200 000 km²) using gravity-based remote sensing. Here we provide evidence that microwave-based remote sensing of soil moisture can be applied to enhance this resolution.

This manuscript focuses on observed changes to the hydrology of 42 rivers in northern Canada draining one-half of its land mass over the period 1964–2013. Statistical and trend analyses are presented for the 42 individual rivers, 6 regional drainage basins, and collectively for all of northern Canada. A main finding is the reversal of a statistically significant decline in the first half of the study period to a statistically significant 18.1 % incline in river discharge across northern Canada.

We examined the variability of daily stable isotopic composition in precipitation in Nanjing, eastern China. We found that both the upstream rainout effect on stable isotopes related to changes in the Asian summer monsoon and the temperature effect of precipitation stable isotopes associated with the Asian winter monsoon should be taken into account when interpreting the stable isotopic composition of speleothems in the Asian monsoon region.

This paper shows an interdisciplinary effort for a common methodology on flood risk analysis: hydraullics, hydrology, climatology and meteorology. Most basic problems of work with historical information are faced. Firsts results of data collection on historical floods for Catalonia (Ne Spain) are showed for period AD 1035-2014.