Analyzing the discharge regime of a large tropical river through remote sensing, ground-based climatic data, and modeling

This study demonstrates the potential for applying passive microwave satellite sensor data to infer the discharge dynamics of large river systems using the main stem Amazon as a test case. The methodology combines (1) interpolated ground-based meteorological station data, (2) horizontally and vertically polarized temperature differences (HVPTD) from the 37-GHz scanning multichannel microwave radiometer (SMMR) aboard the Nimbus 7 satellite, and (3) a calibrated water balance/water transport model (WBM/WTM). Monthly HVPTD values at 0.25° (latitude by longitude) resolution were resampled spatially and temporally to produce an enhanced HVPTD time series at 0.5° resolution for the period May 1979 through February 1985. Enhanced HVPTD values were regressed against monthly discharge derived from the WBM/WTM for each of 40 grid cells along the main stem over a calibration period from May 1979 to February 1983 to provide a spatially contiguous estimate of time-varying discharge. HVPTD-estimated flows generated for a validation period from March 1983 to February 1985 were found to be in good agreement with both observed arid modeled discharges over a 1400-km section of the main stem Amazon. This span of river is bounded downstream by a region of tidal influence and upstream by low sensor response associated with dense forest canopy. Both the WBM/WTM and HVPTD-derived flow rates reflect the significant impact of the 1982–1983 El Niño-;Southern Oscillation (ENSO) event on water balances within the drainage basin

Integrating hydrological modelling and ecosystem functioning for environmental flows in climate change scenarios in the Zambezi River (Zambezi Region, Namibia)

The Zambezi-Chobe wetlands in Namibia are of great international importance for trans-boundary water management because of their remarkable ecological characteristics and the variety and magnitude of the ecosystem services provided. The main objective of this study is to establish the hydro-ecological baseline for the application of environmental flow regimes (EFR). The specific objectives are: (i) the assessment of environmental flow components (EFC) in the current near-natural hydrological conditions; (ii) the generation of future scenarios for climatic and socioeconomic changes; (iii) the estimation of the area duration curves and estimated annual habitat during the inundation of the critical habitats for fisheries (mulapos), under the existing conditions and future scenarios; and (iv) to provide a framework for the future application of EFRs, based on hydrological and ecological processes. To make a sound analysis of the ecological implications, first we develop a conceptual framework of the linkages between the hydrological and biological processes concerning fish communities, because of the critical role of fisheries in the region. The EFCs in near-natural hydrological conditions provide the basis for developing interim EFRs in the region, within the framework of an adaptive management of water resources. The future scenarios indicate a mitigation of the flow variability; and, in the worst-case scenario, the reduction of the maximum flow and inundated area of the mulapos would result in a reduction of the estimated annual habitat of 22%. This means a reduction in the spawning habitats for quiet-water species, in the food resources for fry and juvenile fish and a consequent reduction in fish stocks. Furthermore, the habitat loss during low events is similar and greater under both scenarios, at ca. 35%. Here we corroborate that the EFCs and their variability may become the building blocks of flow-ecology models that lead to environmental flow recommendations, monitoring and research programmes and flow protection activities.This research was part of the research project CERPA (Certification of Protected Areas), funded by the German Federal Ministry of Education and Research (BMBF), and focused on the evaluation of new market-based instruments for biodiversity conservation and their socioeconomic implications. The authors also thank two anonymous reviewers who provided substantial input that improved the manuscript. The study has been partially funded by the national research project IMPADAPT (CGL2013-48424-C2-1-R), with MINECO (Spanish Ministry of Economy) and FEDER funds.Martinez-Capel, F.; García López, L.; Beyer, M. (2017). Integrating hydrological modelling and ecosystem functioning for environmental flows in climate change scenarios in the Zambezi River (Zambezi Region, Namibia). River Research and Applications. 33(2):258-275. https://doi.org/10.1002/rra.3058S25827533

GRDC - status report 1993

A global database of hydrological data is considered necessary for research and application-oriented hydrological and climatological projects which are undertaken on regional and global scales. These projects include basin-oriented, regional and global water balance studies, investigation of trends in long-term hydrological time series, flux of fresh water and matter into the oceans, the coupling of runoff with water quality data and the coupling of hydrological and meteorological models. The project A.5 of the World Meteorological Organization (WMO) under the World Climate Programme-Water (WCP-Water) provides a general service for the collection, storage and dissemination of internationally available sets of hydrological data. Since 1988, the Global Runoff Data Centre (GRDC) is performing this task. (orig.)Available from TIB Hannover: RR 4732(4) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

GRDC status report 1997

SIGLEAvailable from TIB Hannover: RR 4732(18)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Hydrological regimes of the 20 largest rivers of the world A compilation of the GRDC database

An international data base of hydrological data is considered necessary for the validation of Global Circulation Models (GCM's), the detection of regional and global changes in the hydrological regimes and various aspects of water resources development and management. In this GRDC report 20 rivers have been compiled, including the 15 largest rivers of the world in terms of mean monthly discharge as well as the 15 largest rivers in terms of drainage basin size (MARCINEK, ROSENKRANZ, 1989). The objective of the report is the presentation of the entire GRDC data base for these rivers as of June 1994 and the visualization of general regime characteristics for the rivers and major tributaries. For the first time, the location of the GRDC - stations are shown in maps of the drainage basin for each river. (orig.)Available from TIB Hannover: RR 4732(5) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Analysis of long runoff series of selected rivers of the Asia-Pacific region in relation with climate change and El Nino effects

SIGLEAvailable from TIB Hannover: RR 4732(21) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekWorld Meteorological Organization (WMO), Geneva (Switzerland)DEGerman

Dokumentation bestehender Algorithmen zur Uebertragung von Abflusswerten auf Gitternetze

The components of the water cycle represent important links in the climate system between atmosphere, oceans and land surfaces. Within coupled atmospher-ocean-models the hydrologic system itself is described fairly inadequate, and incorrect calculations within General Circulation Models (GCM) may result. Flohn (1992) estimated an error of about 20 % in atmospheric parameters because of unsufficient modeling of the water cycle. Within the World Climate Programme-Water Project B.3 which is under the auspices of the WMO the need of runoff data transformed into a gridded format was proposed. These data should be used for validation of the results of GCM-simulations as well as for the comparison with simulated flows resulted from macro-scale hydrological simulation models. To suite different databases and requirements by the models two grid sizes were considered within the WCP-Water Project B.3: A 0.5 x 0.5 grid used for operations within precise netted models and a 2.5 x 2.5 grid for a coarser resolution. This paper reports on the presentation of different algorithms for calculating grid based runoff data: A. Statistical methods. 1: interpolation methods: areal weighted interpolation; local weighted interpolation; interpolation using isohypsometric maps; rectification method for estimated runoff. 2: empirical methods. B. Mathematical Models for calculating runoff. (orig.)SIGLEAvailable from TIB Hannover: RR 4732(2) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Use of GRDC data 1993 - 1999 A comprehensive summary

SIGLEAvailable from TIB Hannover: RR 4732(24)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman