scholarly journals Closing the water cycle from observations across scales: Where do we stand?

2021 ◽  
pp. 1-95
Author(s):  
Wouter Dorigo ◽  
Stephan Dietrich ◽  
Filipe Aires ◽  
Luca Brocca ◽  
Sarah Carter ◽  
...  
Keyword(s):  
Hydrological Cycle ◽  
Water Cycle ◽  
Global Climate ◽  
Spatial Scales ◽  
Spatial And Temporal Scales ◽  
Mitigation And Adaptation ◽  
Consistent Assessment ◽  
Earth’S Climate ◽  
Improved Model

AbstractLife on Earth vitally depends on the availability of water. Human pressure on freshwater resources is increasing, as is human exposure to weather-related extremes (droughts, storms, floods) caused by climate change. Understanding these changes is pivotal for developing mitigation and adaptation strategies. The Global Climate Observing System (GCOS) defines a suite of Essential Climate Variables (ECVs), many related to the water cycle, required to systematically monitor the Earth's climate system. Since long-term observations of these ECVs are derived from different observation techniques, platforms, instruments, and retrieval algorithms, they often lack the accuracy, completeness, resolution, to consistently to characterize water cycle variability at multiple spatial and temporal scales.Here, we review the capability of ground-based and remotely sensed observations of water cycle ECVs to consistently observe the hydrological cycle. We evaluate the relevant land, atmosphere, and ocean water storages and the fluxes between them, including anthropogenic water use. Particularly, we assess how well they close on multiple temporal and spatial scales. On this basis, we discuss gaps in observation systems and formulate guidelines for future water cycle observation strategies. We conclude that, while long-term water-cycle monitoring has greatly advanced in the past, many observational gaps still need to be overcome to close the water budget and enable a comprehensive and consistent assessment across scales. Trends in water cycle components can only be observed with great uncertainty, mainly due to insufficient length and homogeneity. An advanced closure of the water cycle requires improved model-data synthesis capabilities, particularly at regional to local scales.

scholarly journals Hydro-Meteorological Trends in an Austrian Low-Mountain Catchment

Climate ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 122
Author(s):  
Gerald Krebs ◽  
David Camhy ◽  
Dirk Muschalla
Keyword(s):  
Hydrological Cycle ◽  
Potential Evapotranspiration ◽  
Remote Sensing Data ◽  
Kendall Test ◽  
Adaptation Measures ◽  
Mitigation And Adaptation ◽  
Regional Impacts ◽  
Long Term Trends ◽  
Annual Scale

While ongoing climate change is well documented, the impacts exhibit a substantial variability, both in direction and magnitude, visible even at regional and local scales. However, the knowledge of regional impacts is crucial for the design of mitigation and adaptation measures, particularly when changes in the hydrological cycle are concerned. In this paper, we present hydro-meteorological trends based on observations from a hydrological research basin in Eastern Austria between 1979 and 2019. The analyzed variables include air temperature, precipitation, and catchment runoff. Additionally, the number of wet days, trends for catchment evapotranspiration, and computed potential evapotranspiration were derived. Long-term trends were computed using a non-parametric Mann–Kendall test. The analysis shows that while mean annual temperatures were decreasing and annual temperature minima remained constant, annual maxima were rising. Long-term trends indicate a shift of precipitation to the summer, with minor variations observed for the remaining seasons and at an annual scale. Observed precipitation intensities mainly increased in spring and summer between 1979 and 2019. Catchment actual evapotranspiration, computed based on catchment precipitation and outflow, showed no significant trend for the observed time period, while potential evapotranspiration rates based on remote sensing data increased between 1981 and 2019.

scholarly journals Developing and Demonstrating Climate Indicators for Monitoring the Changing Water Cycle

2016 ◽  
Vol 2016 ◽  
pp. 1-18 ◽  
Author(s):  
Xia Feng ◽  
Paul Houser
Keyword(s):  
Water Cycle ◽  
Spatial Scales ◽  
Atmospheric Moisture ◽  
Spatial Correlations ◽  
Climate Indicators ◽  
Terrestrial Water ◽  
The Mean ◽  
Atmospheric Moisture Content ◽  
Daily Total

In this study, we developed a suite of spatially and temporally scalable Water Cycle Indicators (WCI) to examine the long-term changes in water cycle variability and demonstrated their use over the contiguous US (CONUS) during 1979–2013 using the MERRA reanalysis product. The WCI indicators consist of six water balance variables monitoring the mean conditions and extreme aspects of the changing water cycle. The variables include precipitation (P), evaporation (E), runoff (R), terrestrial water storage (dS/dt), moisture convergence flux (C), and atmospheric moisture content (dW/dt). Means are determined as the daily total value, while extremes include wet and dry extremes, defined as the upper and lower 10th percentile of daily distribution. Trends are assessed for annual and seasonal indicators at several different spatial scales. Our results indicate that significant changes have occurred in most of the indicators, and these changes are geographically and seasonally dependent. There are more upward trends than downward trends in all eighteen annual indicators averaged over the CONUS. The spatial correlations between the annual trends in means and extremes are statistically significant across the country and are stronger forP,E,R, andCcompared todS/dtanddW/dt.

scholarly journals Comparison of satellite-based evapotranspiration estimates over the Tibetan Plateau

2016 ◽  
Vol 20 (8) ◽  
pp. 3167-3182 ◽  
Author(s):  
Jian Peng ◽  
Alexander Loew ◽  
Xuelong Chen ◽  
Yaoming Ma ◽  
Zhongbo Su
Keyword(s):  
Tibetan Plateau ◽  
Vegetation Index ◽  
Water Cycle ◽  
Global Climate ◽  
Spatial Scales ◽  
Accurate Estimation ◽  
The Tibetan Plateau ◽  
North West ◽  
Comparison Results ◽  
Normalised Difference Vegetation Index

Abstract. The Tibetan Plateau (TP) plays a major role in regional and global climate. The understanding of latent heat (LE) flux can help to better describe the complex mechanisms and interactions between land and atmosphere. Despite its importance, accurate estimation of evapotranspiration (ET) over the TP remains challenging. Satellite observations allow for ET estimation at high temporal and spatial scales. The purpose of this paper is to provide a detailed cross-comparison of existing ET products over the TP. Six available ET products based on different approaches are included for comparison. Results show that all products capture the seasonal variability well with minimum ET in the winter and maximum ET in the summer. Regarding the spatial pattern, the High resOlution Land Atmosphere surface Parameters from Space (HOLAPS) ET demonstrator dataset is very similar to the LandFlux-EVAL dataset (a benchmark ET product from the Global Energy and Water Cycle Experiment), with decreasing ET from the south-east to north-west over the TP. Further comparison against the LandFlux-EVAL over different sub-regions that are decided by different intervals of normalised difference vegetation index (NDVI), precipitation, and elevation reveals that HOLAPS agrees best with LandFlux-EVAL having the highest correlation coefficient (R) and the lowest root mean square difference (RMSD). These results indicate the potential for the application of the HOLAPS demonstrator dataset in understanding the land–atmosphere–biosphere interactions over the TP. In order to provide more accurate ET over the TP, model calibration, high accuracy forcing dataset, appropriate in situ measurements as well as other hydrological data such as runoff measurements are still needed.

scholarly journals Fully Automated Light Precipitation Detection from MPLNET and EARLINET Network Lidar Measurements

2020 ◽  
Vol 237 ◽  
pp. 05006
Author(s):  
Simone Lolli ◽  
Gemine Vivone ◽  
Ellsworth J. Welton ◽  
Jasper R. Lewis ◽  
James R. Campbell ◽  
...  
Keyword(s):  
Climate Models ◽  
Hydrological Cycle ◽  
Water Cycle ◽  
Global Climate ◽  
Global Scale ◽  
Global Climate Models ◽  
Morphological Filters ◽  
Lidar Measurements ◽  
Life On Earth ◽  
Light Precipitation

The water cycle strongly influence life on Earth and precipitation especially modifies the atmospheric column thermodynamics through the evaporation process and serving as a proxy for latent heat modulation. For this reason, a correct light precipitation parameterization at global scale, it is of fundamental importance, bedsides improving our understanding of the hydrological cycle, to reduce the associated uncertainty of the global climate models to correctly forecast future scenarios. In this context we developed a full automatic algorithm based on morphological filters that, once operational, will make available a new rain product for the NASA Micropulse Lidar Network (MPLNET) and the European Aerosol Research Lidar Network (EARLINET) in the frame of WMO GALION Project

scholarly journals Earth's water reservoirs in a changing climate

2020 ◽  
Vol 476 (2236) ◽  
pp. 20190458 ◽  
Author(s):  
Graeme L. Stephens ◽  
Julia M. Slingo ◽  
Eric Rignot ◽  
John T. Reager ◽  
Maria Z. Hakuba ◽  
...  
Keyword(s):  
Sea Level ◽  
Hydrological Cycle ◽  
Water Cycle ◽  
Water Reservoirs ◽  
Future Evolution ◽  
Quantitative Understanding ◽  
Global Mean Sea Level ◽  
Earth’S Climate ◽  
The Many ◽  
Different Sources

Progress towards achieving a quantitative understanding of the exchanges of water between Earth's main water reservoirs is reviewed with emphasis on advances accrued from the latest advances in Earth Observation from space. These exchanges of water between the reservoirs are a result of processes that are at the core of important physical Earth-system feedbacks, which fundamentally control the response of Earth's climate to the greenhouse gas forcing it is now experiencing, and are therefore vital to understanding the future evolution of Earth's climate. The changing nature of global mean sea level (GMSL) is the context for discussion of these exchanges. Different sources of satellite observations that are used to quantify ice mass loss and water storage over continents, how water can be tracked to its source using water isotope information and how the waters in different reservoirs influence the fluxes of water between reservoirs are described. The profound influence of Earth's hydrological cycle, including human influences on it, on the rate of GMSL rise is emphasized. The many intricate ways water cycle processes influence water exchanges between reservoirs and thus sea-level rise, including disproportionate influences by the tiniest water reservoirs, are emphasized.

Stochastic stress-testing approach for assessing resilience of urban water systems from source to tap

2021 ◽  
Author(s):  
Dionysios Nikolopoulos ◽  
Panagiotis Kossieris ◽  
Christos Makropoulos
Keyword(s):  
Stress Testing ◽  
Water Cycle ◽  
Spatial Scales ◽  
Water System ◽  
Water Systems ◽  
Distribution Model ◽  
Generation Model ◽  
Urban Water ◽  
Urban Water Systems

<p>Urban water systems are designed with the goal of delivering their service for several decades.  The infrastructure will inevitably face long-term uncertainty in a multitude of parameters from the hydroclimatic and socioeconomic realms (e.g., climate change, limited supply of water in terms quantity and acceptable quality, population growth, shifting demand patterns, industrialization), as well as from the conceptual realm of the decision maker (e.g., changes in policy, system maintenance incentives, investment rate, expansion plans). Because urban water systems are overly complex, a holistic analysis involves the use of various models that individually pertain to a smaller sub-system and a variety of metrics to assess performance, whereas the analysis is accomplished at different temporal and spatial scales for each sub-system. In this work, we integrate a water resources management model with a water distribution model and a water demand generation model at smaller (household and district) scale, allowing us to simulate urban water systems “from source to tap”, covering the entire water cycle. We also couple a stochastic simulation module that supports the representation of uncertainty throughout the water cycle. The performance of the integrated system under long term uncertainty is assessed with the novel measure of system’s resilience i.e. the degree to which a water system continues to perform under progressively increasing disturbance. This evaluation is essentially a framework of systematic stress-testing, where the disturbance is described via stochastically changing parameters in an ensemble of scenarios that represent future world views. The framework is showcased through a synthesized case study of a medium-sized urban water system.</p><p><strong>Acknowledgement</strong></p><p>This research is carried out / funded in the context of the project “A resilience assessment framework for water supply infrastructure under long-term uncertainty: A Source-to-Tap methodology integrating state of the art computational tools” (MIS 5049174) under the call for proposals “Researchers' support with an emphasis on young researchers- 2nd Cycle”. The project is co-financed by Greece and the European Union (European Social Fund- ESF) by the Operational Programme Human Resources Development, Education and Lifelong Learning 2014-2020.”</p>

Adaptation to Global-Warming-Triggered Water Disasters Measures Taken by Science Council of Japan

2009 ◽  
Vol 4 (1) ◽  
pp. 3-6
Author(s):  
Syunsuke Ikeda ◽  
◽  
Keyword(s):  
Climate Change ◽  
Paradigm Shift ◽  
Global Climate ◽  
Social Changes ◽  
Development Programs ◽  
Adaptation Measures ◽  
Mitigation And Adaptation ◽  
The Social ◽  
The Government

As pointed out by Assessment Report 4 of IPCC, global climate change will increase the magnitude and frequency of water-related disasters such as flooding, surge and drought. In addition to this the social changes such as population problems in Japan will aggravate the vulnerability to the disasters. Two concepts to cope with the water-related disasters triggered by climate change are adaptation and mitigation. Though abatement of GHG gas emissions has been eagerly argued, Japan should be more concerned with and take the initiative both for mitigation and adaptation. As adaptation measures for water-related disasters, 3 measures are proposed in this paper; building disaster-awareness societies, building physical/social structures, and adaptation R&D. In addition to them, it is necessary to bring reconstruction of the national land into medium- and long term views as paradigm shift. In this paper, the following recommendations are proposed for the adaptation: the Japanese government should be aware of the importance of adaptation and strongly promote adaptation to mitigate water-related disasters, and the government should also cooperate in establishing adaptation in sustaining development of Asian monsoon areas and development programs.

Estimates of the Global Water Budget and Its Annual Cycle Using Observational and Model Data

2007 ◽  
Vol 8 (4) ◽  
pp. 758-769 ◽  
Author(s):  
Kevin E. Trenberth ◽  
Lesley Smith ◽  
Taotao Qian ◽  
Aiguo Dai ◽  
John Fasullo
Keyword(s):  
Annual Cycle ◽  
Hydrological Cycle ◽  
Water Cycle ◽  
Atmospheric Moisture ◽  
Community Land Model ◽  
Atmospheric Forcings ◽  
Annual Means ◽  
Climate Analysis ◽  
The Tropics

Abstract A brief review is given of research in the Climate Analysis Section at NCAR on the water cycle. Results are used to provide a new estimate of the global hydrological cycle for long-term annual means that includes estimates of the main reservoirs of water as well as the flows of water among them. For precipitation P over land a comparison among three datasets enables uncertainties to be estimated. In addition, results are presented for the mean annual cycle of the atmospheric hydrological cycle based on 1979–2000 data. These include monthly estimates of P, evapotranspiration E, atmospheric moisture convergence over land, and changes in atmospheric storage, for the major continental landmasses, zonal means over land, hemispheric land means, and global land means. The evapotranspiration is computed from the Community Land Model run with realistic atmospheric forcings, including precipitation that is constrained by observations for monthly means but with high-frequency information taken from atmospheric reanalyses. Results for E − P are contrasted with those from atmospheric moisture budgets based on 40-yr ECMWF Re-Analysis (ERA-40) data. The latter show physically unrealistic results, because evaporation often exceeds precipitation over land, especially in the Tropics and subtropics.

scholarly journals The CALIPSO Mission

2010 ◽  
Vol 91 (9) ◽  
pp. 1211-1230 ◽  
Author(s):  
D. M. Winker ◽  
J. Pelon ◽  
J. A. Coakley ◽  
S. A. Ackerman ◽  
R. J. Charlson ◽  
...  
Keyword(s):  
Global Climate ◽  
Radiation Budget ◽  
Atmospheric Measurements ◽  
Joint Project ◽  
Space Agency ◽  
Early Results ◽  
Infrared Spectral ◽  
Passive Sensors ◽  
Earth’S Climate

Aerosols and clouds have important effects on Earth's climate through their effects on the radiation budget and the cycling of water between the atmosphere and Earth's surface. Limitations in our understanding of the global distribution and properties of aerosols and clouds are partly responsible for the current uncertainties in modeling the global climate system and predicting climate change. The CALIPSO satellite was developed as a joint project between NASA and the French space agency CNES to provide needed capabilities to observe aerosols and clouds from space. CALIPSO carries CALIOP, a two-wavelength, polarization-sensitive lidar, along with two passive sensors operating in the visible and thermal infrared spectral regions. CALIOP is the first lidar to provide long-term atmospheric measurements from Earth's orbit. Its profiling and polarization capabilities offer unique measurement capabilities. Launched together with the CloudSat satellite in April 2006 and now flying in formation with the A-train satellite constellation, CALIPSO is now providing information on the distribution and properties of aerosols and clouds, which is fundamental to advancing our understanding and prediction of climate. This paper provides an overview of the CALIPSO mission and instruments, the data produced, and early results.

scholarly journals Long-term thermal sensitivity of Earth’s tropical forests

Science ◽  
2020 ◽  
Vol 368 (6493) ◽  
pp. 869-874 ◽  
Author(s):  
Martin J. P. Sullivan ◽  
Simon L. Lewis ◽  
Kofi Affum-Baffoe ◽  
Carolina Castilho ◽  
Flávia Costa ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Climate Adaptation ◽  
Global Climate ◽  
Thermal Sensitivity ◽  
Forest Carbon ◽  
Maximum Temperature ◽  
Permanent Plots ◽  
Short Term ◽  
Earth’S Climate

The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate.

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