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Future climate scenarios of the Global Circulation model (GCM) show an increased frequency of heavy rainfall events, which may lead to more severe floods. It is also expected that more and more areas will suffer due to flooding as a result of growing urbanization. Public attention has increased in many parts of the world in recent years and calls have been made to improve flood warnings, including the United States, the European Union and Australia (Hapuarachchi, H.A.P, and Q.J. Wang 2008). To respond and manage flood hazard there is a need to provide a high spatial resolution flood forecast and with sufficient lead time. This study presents an approach for creation of a forecast model based on the analysis of historical hydrometeorological data from conventional and automatic monitoring networks of the National Institute of Meteorology and Hydrology in Bulgaria. The study area is the downstream Kamchia river watershed. Real-time water level observations and calculated discharges based on temporary rating curves are used to dynamically adjust the runoff forecasting. In this paper an approach for combining a hydrological model (TOPKAPI) and a twodimensional hydraulic model (HEC-RAS) for flood simulation is presented. Hydrological modelling is used for forecasting the outflow at a hydrometric station (43800) on Kamchia River near the village of Grozdyovo. The 2D hydraulic HEC-RAS model is used for simulating rainfall - runoff process in Kamchia watershed downstream of the village of Grozdyovo and the results from the hydrological modeling are used as an input data. In this paper the results of using operational hydrological data and forecast precipitation totals for flood simulation is presented. [ABSTRACT FROM AUTHOR]

Variabilities and changes due to natural and anthropogenic causes in the water cycle always presented a challenge for water management planning. Practitioners traditionally coped with variabilities in the hydrological processes by assuming stationarity in the probability distributions and attempted to address non-stationarity by revising this probabilistic properties via continued hydro-climatological observations. Recently, this practice was questioned and more reliance on Global Circulation Models was put forward as an alternative for water management plannig. This paper takes a brief assessment of the state of Global Circulation Models (GCM) and their applications by presenting case studies over Global, European and African domains accompanied by literature examples. Our paper demonstrates core deficiencies in GCM based water resources assessments and articulates the need for improved Earth system monitoring that is essential not only for water managers, but to aid the improvements of GCMs in the future. [ABSTRACT FROM AUTHOR]

This study aims to analyze future snowmelt runoff and snow extent for the Upper Euphrates Basin (41 109 km 2) which is the most upstream basin of the water tower Mesopotamia and located in the Eastern mountainous part of Türkiye. The future characterization of snowmelt runoff and snow water equivalent is investigated taking the regional climate model projections into account through hydrological model applications. The basin is divided into two major sub-basins Karasu Basin and Murat Basin. The conceptual hydrological models, HBV and HEC-HMS have been utilized to establish a rainfall-runoff relationship. The models are calibrated and validated with observed daily total precipitation and average temperature data for the 1980–2011 period. Future projections are selected for the 2025–2100 periods using EU-CORDEX data with various global circulation models. MPI-ESM-LR and CNRM-CM5 data sets and RCP4.5 and RCP8.5 emission scenarios are used for future projections. The results indicate a decrease in snow cover extent and an increase in snowmelt runoff. The overall assessment will help us to understand how these changes will affect the operations of water resources systems (downstream reservoirs) in terms of flood control, energy production, irrigation, water supply, etc. [ABSTRACT FROM AUTHOR]

In the last decades the constant increase of the economical activities in the Black Sea basin, enhanced the importance of a better prediction of the global and local circulation in this environment. Moreover, the global changes in the climate often induce unusual environmental patterns and various new scenarios should be also considered. The aim of the work proposed herewith is to present the results of an implementation of such a circulation modeling system for the entire basin of the Black Sea. The model considered is MOHID (acronym from MOdelação HIDrodinamica) three-dimensional water modeling system, which is developed by MARETEC (Marine and Environmental Technology Research Center) at Instituto Superior Técnico (IST) in Lisbon. The paper presents simulations, carried out for the month of January 2010, that were compared with remotely sensed data corresponding to the same period. The above simulations were performed on three dimensions (35 depth layers), taking into account the temperature and salinity fields provided by the MyOcean website (http://www.myocean.eu/). Some original MATLAB software with numerical and graphical outputs was also developed for pre and post processing the data associated with the numerical model simulations in the Black Sea basin. [ABSTRACT FROM AUTHOR]

Current parameterization of radiation in the CPTEC’s (Center for Weather Forecast and Climate Studies, Cachoeira Paulista, SP, Brazil) operational AGCM has its origins in the work of Harshvardhan et al. (1987) and uses the formulation of Ramaswamy and Freidenreich (1992) for the short-wave absorption by water vapor. The UK Met Office’s radiation code (Edwards and Slingo, 1996) was incorporated into CPTEC’s global model, initially for short-wave only, and some impacts of that were shown by Chagas and Barbosa (2006). Current paper presents some impacts of the complete incorporation (both short-wave and long-wave) of UK Met Office’s scheme. Selected results from off-line comparisons with line-by-line benchmark calculations are shown. Impacts on the AGCM’s climate are assessed by comparing output of climate runs of current and modified AGCM with products from GEWEX/SRB (Surface Radiation Budget) project. [ABSTRACT FROM AUTHOR]

Nowadays, special attention is paid to hydroelectric production because it is an efficient, reliable, and renewable source of energy, especially in developing countries like Cameroon, where hydropower potential is the main source of electricity production. It also represents a useful tool to reduce the atmospheric greenhouse gas concentrations caused by human activities. However, it is the most sensitive industry to global warming, mainly because climate change will directly affect the quality, quantity of water resources (streamflow and runoff), which are the important drivers of hydropower potential. This study examined the response of hydropower potential to climate change on the Lagdo dam located in the Benue River Basin, Northern Cameroon. Hydropower potential was computed based on streamflow simulated using HBV-Light hydrological model with dynamically downscaled temperature and precipitation from the regional climate model REMO. These data were obtained using the boundary conditions of two general circulation models (GCMs): the Europe-wide Consortium Earth System Model (EC-Earth) and the Max Planck Institute-Earth System Model (MPI-ESM) under three Representative Concentrations Pathways (RCP2.6, RCP4.5 and RCP8.5). The results suggest that, the combination of decreased precipitation and streamflow, increased PET will negatively impact the hydropower potential in the Lagdo dam under climate change scenarios, models and future periods. [ABSTRACT FROM AUTHOR]

In last decades, the impact of climate change started to appear in the semi-arid regions of the Mediterranean Basin. The severity and frequency of drought events in Northwestern Algeria have affected water resources availability and agriculture. This study aims to evaluate the temporal evolution of drought events characteristics, such as drought duration, frequency and severity, of the Beni Bahdel Dam catchment, Northwestern Algeria. Drought characteristics have been derived from the Standardized precipitation index (SPI) computed for the period from 1941 to 2100 using precipitation data from observations and simulations of the regional climate model RCA4 (Rossby Centre Atmosphere model, version 4). The RCA4 model was forced by the global circulation model MPI-ESM-LR under two Representative Concentration Pathways (RCPs) scenarios. The ability of the model simulations was firstly assessed to reproduce the drought characteristics from observed data (1951–2005). Then, future changes in drought characteristics over the twenty-first century were investigated under the two scenarios (RCP4.5 and RCP8.5). Results show an amplification of drought frequencies and durations in the future under the RCP8.5 scenario. [ABSTRACT FROM AUTHOR]

The Indian Ocean Dipole (IOD) signature in European summertime surface air temperature (SAT) and sea level pressure (SLP) fields were investigated in this study. The SAT and SLP anomalies of the surface fields over the European region associated with the IOD variability are described based on the results of experiments with atmospheric general circulation model and re-analysis data. It is shown that the prevalent positive significant SAT/SLP anomaly tends to form over Central/Eastern Europe in the negative phase of the IOD events. That accompanied by weak and insignificant negative SAT/SLP anomalies in July-August over Western Europe. The opposite anomalies in sign have appeared in the positive IOD phase. The ensemble simulation gave evidence that the European summertime atmospheric response carries the nonlinear effect on stepping up the values of SST IOD anomalies in the Indian Ocean. The composite difference between the negative and positive phases of the IOD, constructed based on the re-analysis of 20CR data, generally confirms the described simulation results of the ensemble climate model for the SAT/SLP fields. However, it can be only noted a slight shift toward the east of the European region in 20CR reanalysis data compared with the simulation. In addition, the amplitude of the obtained pattern based on 20CR re-analysis has 2-3 times high values than in the simulations. It might have resulted from the low 20CR re-analysis cases with pure IOD years in the last century, when the other oscillations (North Atlantic oscillation, El Nino-Southern oscillation and others) are in the neutral phase. [ABSTRACT FROM AUTHOR]

A methodology for regional assessment of current and future water availability in Europe is presented in this study. The methodology is based on a proposed indicator of risk of water scarcity based on the projections of runoff and water availability for European countries. The risk of water scarcity is the combined result of hydrological processes, which determine streamflow in natural conditions, and human intervention, which determines water management using the available hydraulic infrastructure and establishes water supply conditions through operating rules. Model results show that changes in runoff and availability obtained for individual GCM projections can be large and even contradictory. These heterogeneous results are summarized in the water scarcity risk index, a global value that accounts for the results obtained with the ensemble of model results and emission scenarios. The countries at larger risk are (in this order) Spain, Portugal, Macedonia, Greece, Bulgaria, Albania, France and Italy. They are mostly Mediterranean countries already exposed to significant water scarcity problems. There are countries, like Slovakia, Ireland, Belgium, Luxembourg, Croatia and Romania, with mild risk. Northern Arctic countries, like Sweden, Finland, Norway and Russia, show a robust however mild increase in water availability. [ABSTRACT FROM AUTHOR]

The present study was carried out within the framework of the International Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP) for 11 large river basins located in different continents of the globe under a wide variety of natural conditions. The aim of the study was to investigate possible changes in various characteristics of annual river runoff (mean values, standard deviations, frequency of extreme annual runoff) up to 2100 on the basis of application of the land surface model SWAP and meteorological projections simulated by five General Circulation Models (GCMs) according to four RCP scenarios. Analysis of the obtained results has shown that changes in climatic runoff are different (both in magnitude and sign) for the river basins located in different regions of the planet due to differences in natural (primarily climatic) conditions. The climatic elasticities of river runoff to changes in air temperature and precipitation were estimated that makes it possible, as the first approximation, to project changes in climatic values of annual runoff, using the projected changes in mean annual air temperature and annual precipitation for the river basins. It was found that for most rivers under study, the frequency of occurrence of extreme runoff values increases. This is true both for extremely high runoff (when the projected climatic runoff increases) and for extremely low values (when the projected climatic runoff decreases). [ABSTRACT FROM AUTHOR]

Climate change impact on river runoff was investigated within the framework of the second phase of the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP2) using a physically-based land surface model Soil Water - Atmosphere - Plants (SWAP) (developed in the Institute of Water Problems of the Russian Academy of Sciences) and meteorological projections (for 2006-2099) simulated by five General Circulation Models (GCMs) (including GFDL-ESM2M, HadGEM2-ES, IPSL-CM5A-LR, MIROC-ESM-CHEM, and NorESM1-M) for each of four Representative Concentration Pathway (RCP) scenarios (RCP2.6, RCP4.5, RCP6.0, and RCP8.5). Eleven large-scale river basins were used in this study. First of all, SWAP was calibrated and validated against monthly values of measured river runoff with making use of forcing data from theWATCH data set and all GCMs' projections were bias-corrected to the WATCH. Then, for each basin, 20 projections of possible changes in river runoff during the 21st century were simulated by SWAP. Analysis of the obtained hydrological projections allowed us to estimate their uncertainties resulted from application of different GCMs and RCP scenarios. On the average, the contribution of different GCMs to the uncertainty of the projected river runoff is nearly twice larger than the contribution of RCP scenarios. At the same time the contribution of GCMs slightly decreases with time. [ABSTRACT FROM AUTHOR]

Rainfall pattern are good indicators for potential disasters. Global Circulation Model (GCM) contains global scale information that can be used to predict the rainfall data. Statistical downscaling (SD) utilizes the global scale information to make inferences in the local scale. Essentially, SD can be used to predict local scale variables based on global scale variables. SD requires a method to accommodate non linear effects and extreme values. Extreme value Theory (EVT) can be used to analyze the extreme value. One of methods to identify the extreme events is peak over threshold that follows Generalized Pareto Distribution (GPD). The vector generalized additive model (VGAM) is an extension of the generalized additive model. It is able to accommodate linear or nonlinear effects by involving more than one additive predictors. The advantage of VGAM is to handle multi response models. The key idea of VGAM are iteratively reweighted least square for maximum likelihood estimation, penalized smoothing, fisher scoring and additive models. This works aims to analyze extreme rainfall data in Indramayu using VGAM. The results show that the VGAM with GPD is able to predict extreme rainfall data accurately. The prediction in February is very close to the actual value at quantile 75. [ABSTRACT FROM AUTHOR]

The Earth Radiation Budget (ERB) and its geographical distribution is intimately linked with the earth's climate and with the general circulation. We analyze 10 years of global Clouds and the Earth's Radiant Energy System (CERES) measurements from 2000 to 2010 and 8 years of diurnally resolved Geostationary Earth Radiation Budget (GERB) from 2004 to 2011 to illustrate this link and to verify if we can detect climate variability or systematic change. In response to the diurnal wave of solar heating three tropical convection maxima exist over South America, Africa, and around Indonesia. The Indonesian convection maximum is unstable due to a lack of a stabilizing land mass; this is the root cause of the El Ninˇo/La Ninˇa inter-annual variation with a global pattern of teleconnected variations through the general Walker circulation. Since 2000 a change in global dynamics seems to have occurred. There was a general strengthening of La Ninˇa, coinciding with a 'break in global temperature rise', and with an 'eastern dimming', i.e. an increase of aerosols over Asia. There is a resemblance to the period of 'western dimming' from 1945 to 1980, and a contrast with the period of global temperature rise and El Ninˇo strengthening from 1980 to 2000. It is of paramount importance that the suspected link between the eastern dimming, the strengthening of La Ninˇa and the break in global temperature rise is thoroughly investigated. This can best be done by a move of a satellite of the Meteosat Second Generation (MSG) series over the Indian Ocean. MSG provides diurnally resolved measurements of the key variables of the ERB, clouds and aerosols, and of the auxiliary variables of Sea Surface Temperature (SST) and static stability. [ABSTRACT FROM AUTHOR]

A 14C chronological study from sediments in lacustrine environments in Brazil was developed to assess climate and environmental changes during the Holocene. In the middle of the great debate concerning late glacial in Amazonia, the Holocene period has been somewhat forgotten. The Amazonian climate during Holocene was probably drier and certainly more variable than the present-day one. Global Circulation Models (GCM) applied to 6000 BP pointed out that lower summer insolation was the reason of lower precipitations at that time. [ABSTRACT FROM AUTHOR]

We present an analysis of 150+ clouds observed by Cassini VIMS in Titan's atmosphere. Results are compared to general circulation model predictions (GCMs) [ABSTRACT FROM AUTHOR]