scholarly journals Climate Control of Multidecadal Variability in River Discharge and Precipitation in Western Europe

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 257
Author(s):  
Isabel Jalón-Rojas ◽  
Bruno Castelle
Keyword(s):  
Interannual Variability ◽  
River Discharge ◽  
Large Scale ◽  
Western Europe ◽  
River Flow ◽  
Winter Precipitation ◽  
Climate Indices ◽  
Spring Discharge ◽  
Monthly Precipitation ◽  
Climate Control

The influence of large-scale climate variability on winter river discharge and precipitation across western Europe is investigated. We analyze 60 years of monthly precipitation and river flow data from 18 major western-European rivers and its relationship with dominant teleconnection patterns and climate indices in this region. Results show that winter river flow is characterized by large interannual variability, best correlates with (a) the North Atlantic Oscillation (NAO) at the far-northern (R up to 0.56) and southern latitudes (R up to −0.72), and (b) the West Europe Pressure Anomaly (WEPA) at the middle and northern latitudes, from 42° N to 55° N (R up to 0.83). These indices also explain the interannual variability in autumn and spring discharge in rivers characterized by secondary floods. Compared to the other leading modes of atmospheric variability, WEPA increases the correlations with winter precipitation up to 0.8 in many regions of western and central Europe. A positive WEPA corresponds to a southward shift and an intensification of the Icelandic-Low/Azores-High dipole, driving enhanced precipitation and river discharge in these regions. The correlations with precipitation are slightly higher than those with river discharge, particularly in France, with clear latitudinal gradient. This trend suggests that water storage variability and other catchment characteristics may also influence the interannual variability of river discharge. Seasonal forecasting of the WEPA and NAO winter indices can become a powerful tool in anticipating hydrological risks in this region.

Satellite soil moisture improves rainfall just where needed

2020 ◽  
Author(s):  
Luca Brocca ◽  
Stefania Camici ◽  
Christian Massari ◽  
Luca Ciabatta ◽  
Paolo Filippucci ◽  
...  
Keyword(s):  
Soil Moisture ◽  
River Discharge ◽  
Large Scale ◽  
River Flow ◽  
Global Scale ◽  
Rain Gauge ◽  
Rainfall Runoff ◽  
Global Precipitation Climatology Centre ◽  
Satellite Rainfall ◽  
Global Precipitation

<p>Soil moisture is a fundamental variable in the water and energy cycle and its knowledge in many applications is crucial. In the last decade, some authors have proposed the use of satellite soil moisture for estimating and improving rainfall, doing hydrology backward. From this research idea, several studies have been published and currently preoperational satellite rainfall products exploiting satellite soil moisture products have been made available.</p><p>The assessment of such products on a global scale has revealed an important result, i.e., the soil moisture based products perform better than state of the art products exactly over regions in which the data are needed: Africa and South America. However, over these areas the assessment against rain gauge observations is problematic and independent approaches are needed to assess the quality of such products and their potential benefit in hydrological applications. On this basis, the use of the satellite rainfall products as input into rainfall-runoff models, and their indirect assessment through river discharge observations is an alternative and valuable approach for evaluating their quality.</p><p>For this study, a newly developed large scale dataset of river discharge observations over 500+ basins throughout Africa has been exploited. Based on such unique dataset, a large scale assessment of multiple near real time satellite rainfall products has been performed: (1) the Early Run version of the Integrated Multi-Satellite Retrievals for GPM (Global Precipitation Measurement), IMERG Early Run, (2) SM2RAIN-ASCAT (https://doi.org/10.5281/zenodo.3405563), and (3) GPM+SM2RAIN (http://doi.org/10.5281/zenodo.3345323). Additionally, gauge-based and reanalysis rainfall products have been considered, i.e., (4) the Global Precipitation Climatology Centre (GPCC), and (5) the latest European Centre for Medium-Range Weather Forecasts reanalysis, ERA5. As rainfall-runoff model, the semi-distributed MISDc (Modello Idrologico Semi-Distribuito in continuo) model has been employed in the period 2007-2018 at daily temporal scale.</p><p>First results over a part of the dataset reveal the great value of satellite soil moisture products in improving satellite rainfall estimates for river flow prediction in Africa. Such results highlight the need to exploit such products for operational systems in Africa addressed to the mitigation of the flood risk and water resources management.</p>

Analysis of Precipitation Patterns and Extremes in European Lowlands

2020 ◽  
Author(s):  
Alexandra Berényi ◽  
Judit Bartholy ◽  
Rita Pongrácz
Keyword(s):  
Large Scale ◽  
Western Europe ◽  
Precipitation Amount ◽  
Weather Conditions ◽  
East European Plain ◽  
Climate Indices ◽  
East European ◽  
Precipitation Patterns ◽  
Weather Patterns ◽  
Management Actions

<p>It is well-known that climate change affects large scale weather patterns and local extremes all over the world as well as in Europe. These changes include the changes of precipitation occurences, amounts, and spatial patterns, which may require appropriate risk management actions. For this purpose, the first step is a thorough analysis of possible hazards associated to specific precipitation-related weather phenomena.</p><p>The primary goals of this study are (i) to examine the changes in precipitation patterns and extremes, and (ii) to explore the possible connections between changes in different lowlands across Europe. Precipitation time series are used from the E-OBS v.20 datasets on a 0.1° regular grid. Datasets are based on station measurements from Europe and are available from 1950 onward with daily temporal resolution. Altogether 14 plain regions are selected in this study to represent different parts within Europe. More specifically, five plain regions are parts of the East European Plain, two regions are located in the Scandinavian basin, five regions are located in Western Europe, and the Pannonian Plain (including mostly Hungary) is also selected. For choosing the plains and their spatial representations, objective criteria are used, namely, the elevation remains under 200 m throughout the defined area and difference between the neighbouring gridpoints within the plain region does not exceed 40 m. Daily precipitation times series are analyzed and compared for these plain regions using various statistical tools. The results represent annual and seasonal changes in average and extreme precipitation amount as well as in the frequency of precipitation occurences. Climate indices and the occurence of extreme weather conditions including wet and dry spells are also analyzed.</p><p> </p>

Trends and variability of climate and river flow in the region of Costa das Baleias, Brazil

2013 ◽  
Vol 67 (1) ◽  
pp. 47-54 ◽  
Author(s):  
F. Genz ◽  
C. A. S. Tanajura
Keyword(s):  
River Discharge ◽  
Large Scale ◽  
River Flow ◽  
Local Development ◽  
Global Climate ◽  
Surface Air Temperature ◽  
Kendall Test ◽  
Positive Trend ◽  
Area Of Interest ◽  
Discharge Rates

There is an ongoing effort by the scientific community to regionalize climate studies to support local development plans. The area of interest is the Costa das Baleias on the east coast of northeast Brazil. It is located in a transition region of precipitation trends, and so assessing the local signal and magnitude is necessary. A series of annual anomalies of surface air temperature, precipitation and river discharge were analyzed from 1946 to 2010. The modified Mann–Kendall test was applied to detect trends. Temperature anomalies showed a consistent positive trend since 1950. Precipitation anomalies tended to decrease, though not significantly. River discharge rates showed a consistent positive trend. However, from the 1980s onwards, both the precipitation and the river discharge anomalies had the same decreasing tendency. The precipitation and discharge behavior are likely due to the combined effect of human interventions in the river basins including local, synoptic and global climate effects. The inter-annual variability was characterized by spectral analysis. Cycles were identified for the precipitation and the river discharge with periods of 2–3 years, 3–4 years, 7–8 years and 11–12 years. The decadal frequency is consistent with the South Atlantic and El Niño indices. This work strongly indicates that climate is changing in Costa das Baleias and further work is needed to investigate the mechanisms that link local to large-scale variability.

scholarly journals Large-scale scour in response to tidal dominance in estuaries

2021 ◽  
Author(s):  
Jasper Leuven ◽  
Daan van Keulen ◽  
Jaap Nienhuis ◽  
Alberto Canestrelli ◽  
Ton Hoitink
Keyword(s):  
Sediment Transport ◽  
River Discharge ◽  
Large Scale ◽  
River Flow ◽  
Tidal Flow ◽  
Tidal Energy ◽  
Local Flow ◽  
Flow Acceleration ◽  
Flow Through ◽  
Tide Interaction

<p>Channel beds in estuaries and deltas often exhibit a local depth maximum at a location close to the coast. There are two known causes of large-scale (i.e. >10 river widths along-channel) channel bed scours: width constriction and draw down during river discharge extremes, both creating a local flow acceleration. Here, we systematically investigate a potential third mechanism. We study the effect of tidal dominance on the equilibrium channel bed in estuaries with a 1D-morphodynamic model. In estuaries, a morphodynamic equibrium is reached when the net (seaward) transport matches the upstream supply along the entire reach. The residual (river) current and river-tide interactions create seaward transport. Herein, river-tide interactions represent the seaward advection of tide-induced suspended sediment by the river flow. Tidal asymmetry typically creates landward transport. The main reason for scour formation is the amplification of tidal flow through funnelling of tidal energy. Only for a scouring profile the drop in river induced current magnitude reduces the river-tide interaction term, so that the net sediment transport matches the upstream sediment transport. When tidal influence is relatively large, and when channel convergence is strong, a equilibrium is only obtained with a scouring profile. We propose a predictor dependent on the width convergence, quantified as S<sub>B</sub>, and on the ratio between the specific peak tidal discharge at the mouth and the specific river discharge at the landward boundary (q<sub>tide</sub>/q<sub>river</sub>). Scours develop if (q<sub>tide</sub>/q<sub>river</sub>)/S<sub>B</sub> exceeds 0.3. These results are independent of scale and allow the prediction of scour in estuaries under future changes.</p>

scholarly journals Linkages between Large-Scale Climate Patterns and Karst Spring Discharge in Northern China

2016 ◽  
Vol 17 (2) ◽  
pp. 713-724 ◽  
Author(s):  
Xueli Huo ◽  
Zhongfang Liu ◽  
Qingyun Duan ◽  
Pengmei Hao ◽  
Yanyan Zhang ◽  
...  
Keyword(s):  
Wavelet Transform ◽  
Time Scales ◽  
Large Scale ◽  
Southern Oscillation ◽  
Northern China ◽  
Climate Indices ◽  
Spring Discharge ◽  
Climate Conditions ◽  
Climate Patterns ◽  
Periodic Components

Abstract The Niangziguan Springs (NS) discharge is used as a proxy indicator of the variability of the karst groundwater system in relation to major climate indices such as El Niño–Southern Oscillation (ENSO), Pacific decadal oscillation (PDO), Indian summer monsoon (ISM), and west North Pacific monsoon (WNPM). The relationships between spring discharge and these climate indices are determined using the multitaper method (MTM), continuous wavelet transform (CWT), and wavelet transform coherence (WTC). Significant periodic components of spring discharge in the 1-, 3.4-, and 26.8-yr periodicities are identified and reconstructed for further investigation of the correlation between spring discharge and large-scale climate patterns on these time scales. Correlation coefficients and WTC between spring discharge and the climate indices indicate that variability in spring discharge is significantly and positively correlated with monsoon indices in the 1-yr periodicity and negatively correlated with ENSO in the 3.4-yr periodicity and PDO in the 26.8-yr periodicity. This suggests that the oscillations of the spring discharge on annual, interannual, and interdecadal time scales are dominated by monsoon, ENSO, and PDO in the NS basin, respectively. Results show that monsoons modulate the spring discharge by affecting local meteorological parameters. ENSO and PDO impact the variability of the NS discharge by affecting the climate conditions in northern China.

scholarly journals Why Is ENSO Influencing Northwest India Winter Precipitation in Recent Decades?

2010 ◽  
Vol 23 (8) ◽  
pp. 1979-1993 ◽  
Author(s):  
R. K. Yadav ◽  
J. H. Yoo ◽  
F. Kucharski ◽  
M. A. Abid
Keyword(s):  
Interannual Variability ◽  
Large Scale ◽  
Southern Oscillation ◽  
India Meteorological Department ◽  
Central India ◽  
Winter Precipitation ◽  
Cyclonic Circulation ◽  
Circulation Anomaly ◽  
Western Disturbances ◽  
Northwest India

Abstract This study examines decadal changes of the El Niño–Southern Oscillation (ENSO) influence on the interannual variability of northwest India winter precipitation (NWIWP). The analysis is based on correlations and regressions performed using India Meteorological Department (IMD) records based on station data and reanalysis fields from 1950 to 2008. The authors find that the interannual variability of NWIWP is influenced by the ENSO phenomenon in the recent decades. This conclusion is supported by a consistency across the different observational datasets employed in this study and confirmed by numerical modeling. A physical mechanism for such an influence is proposed, by which western disturbances (WDs) are intensified over northwest India because of a baroclinic response due to Sverdrup balance related to large-scale sinking motion over the western Pacific during the warm phase of ENSO. This response causes an upper-level cyclonic circulation anomaly north of India and a low-level anticyclonic anomaly over southern and central India. The cyclonic circulation anomaly intensifies the WDs passing over northwest India.

scholarly journals Interannual variability of winter precipitation in the European Alps: relations with the North Atlantic Oscillation

2008 ◽  
Vol 5 (4) ◽  
pp. 2045-2065 ◽  
Author(s):  
E. Bartolini ◽  
P. Claps ◽  
P. D'Odorico
Keyword(s):  
Water Resources ◽  
Interannual Variability ◽  
Large Scale ◽  
Mechanistic Explanation ◽  
Winter Precipitation ◽  
European Alps ◽  
Small Areas ◽  
The North ◽  
The Alps ◽  
The North Atlantic Oscillation

Abstract. The European Alps rely on winter precipitation for various needs in terms of hydropower and other water uses. Major European rivers originate from the Alps and rely on winter precipitation and the consequent spring snow melt for their summer base flows. Understanding the fluctuations in winter rainfall in this region is crucially important to the study of changes in hydrologic regime in streams and rivers, as well as to the management of their water resources. Despite the recognized relevance of winter precipitation to the water resources of the Alps and surrounding regions, the magnitude and mechanistic explanation of interannual precipitation variability in the Alpine region remain unclear and poorly investigated. Here we use gridded precipitation data from the CRU TS 1.2 to study the interannual variability of winter alpine precipitation. We found that the Alps are the region with the highest interannual variability in winter precipitation in Europe. This variability cannot be completely explained by large scale climate patterns such as the AO, NAO or the EA-WR, even though regions below and above the Alps demonstrate connections with these patterns. Significant trends were detected only in small areas within this region, and were of opposite sign between the eastern and western part of the Alps.

Calibration of ECMWF seasonal ensemble precipitation reforecasts in Java (Indonesia) using bias-corrected precipitation and climate indices

2021 ◽  
Author(s):  
DIAN NUR RATRI ◽  
KIRIEN WHAN ◽  
MAURICE SCHMEITS
Keyword(s):  
Large Scale ◽  
Skill Score ◽  
Precipitation Forecast ◽  
Logistic Distribution ◽  
Climate Indices ◽  
Monthly Precipitation ◽  
Seasonal Precipitation ◽  
Post Processing ◽  
Processing Application ◽  
Ensemble Model Output Statistics

AbstractThe seasonal precipitation forecast is one of the essential inputs for economic and agricultural activities and has significant impact on decision making. Large-scale modes of climate variability have strong relationships with seasonal rainfall in Java and are natural candidates for use as potential predictors in a statistical post-processing application. We explore whether using climate indices as additional predictors in the statistical post-processing of ECMWF Seasonal Forecast System 5 (SEAS5) precipitation can improve skill. We use parametric statistical post-processing by applying a logistic distribution-based Ensemble Model Output Statistics (EMOS) technique. We add a variety of potential predictors in the analysis, namely SEAS5 raw and Empirical Quantile Mapping (EQM) bias-corrected precipitation, Nino3.4 index, Dipole Mode Index (DMI), Madden Julian Oscillation (MJO) indices, Sea Surface Temperature (SST) around Java, and several other predictors. We analyze the period of 1981-2010, focusing on July, August, September, and October. We use the Continuous Ranked Probability Skill Score (CRPSS) and Brier Skill Score (BSS) in a comparative verification of raw, EQM and EMOS seasonal precipitation forecasts. We have found that it is essential to use EQM-corrected precipitation as a predictor instead of raw precipitation in the latter. Besides, Nino3.4 and DMI forecasts are not needed as extra predictors to improve monthly precipitation forecasts for the first lead month, except for September. However, for somewhat longer lead months, in September and October when there is more skill than climatology, the model that includes only Nino3.4 and DMI forecasts as potential predictors performs about the same compared to the model that uses only EQM-corrected precipitation as a predictor.

Improved Teleconnective Predictability of Monthly Precipitation Amounts Using Canonical Correlation Analysis

2021 ◽  
Author(s):  
Mahdi Ghamghami ◽  
Javad Bazrafshan
Keyword(s):  
Correlation Analysis ◽  
Canonical Correlation Analysis ◽  
Canonical Correlation ◽  
Lead Time ◽  
Large Scale ◽  
Climate Indices ◽  
Lead Times ◽  
Monthly Precipitation ◽  
Weather Stations ◽  
Monthly Precipitation Data

Abstract This study aimed to evaluate the application of the canonical correlation analysis (CCA) to predict monthly precipitation amounts (predictands) by benefitting from 17 large-scale climate indices (predictors) in Iran. Monthly precipitation data, covering the period of 1987–2017, were collected from 100 weather stations across the country. Monthly precipitations were predicted using the multiple linear regression (MLR) models, based on the 1- to 6-month lead times of the original and canonical predictors. The cross-validation was conducted to compare the prediction skills of the two sets of MLR models constructed on the basis of the original predictors (MLOrigPr) and the canonical predictors (MLCCAPr). The analyses revealed the dominant teleconnections and that there are the interannual variations in responses of precipitation to them suggesting that a signal only is not sufficient to achieve a robust understanding of the associations. At the 1-month lead time, the MLR models based on the canonical predictors outperformed those based on the original predictors. However, the skill of both models was reduced by increasing the lead times up to 6 months. Averaging on all stations, around 61.4% and 26.3% of the observed values falls into the 95% prediction intervals of the MLCCAPr and MLOrigPr models, respectively. Furthermore, the MLCCAPr models were found to be more spatially universal than the MLOrigPr ones. These findings corroborated the advantage of using the CCA in improving the teleconnective predictability of precipitation in Iran.

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