scholarly journals Trends in rainfall erosivity in NE Spain at annual, seasonal and daily scales, 1955–2006

2012 ◽  
Vol 9 (5) ◽  
pp. 6285-6309 ◽  
Author(s):  
M. Angulo-Martínez ◽  
S. Beguería
Keyword(s):  
Soil Degradation ◽  
Bare Soil ◽  
Western Mediterranean ◽  
Rainfall Erosivity ◽  
Spatial And Temporal Variability ◽  
Major Mechanism ◽  
The North ◽  
Mediterranean Oscillation ◽  
The Impact ◽  
Ne Spain

Abstract. Rainsplash – the detachment and transport of soil particles by the impact of raindrops on a bare soil – is a major mechanism of soil degradation and erosion on semiarid areas and agricultural lands. Rainfall erosivity refers to the ability of precipitation to erode soil, and depends on the characteristics of the raindrops – size and velocity – and on the rainfall intensity and duration. Despite the relevance of rainfall erosivity for soil degradation prevention very few studies addressed its spatial and temporal variability. On this study the time variation of rainfall erosivity in the Ebro valley (NE Spain) is assessed for the period 1955–2006. The results show a general decrease in annual and seasonal rainfall erosivity, which is explained by a decrease of very intense rainfall events whilst the frequency of moderate and low events increased. This trend is related to prevailing positive conditions of the main atmospheric teleconnection indices affecting the West Mediterranean, i.e. the North Atlantic Oscillation (NAO), the Mediterranean Oscillation (MO) and the Western Mediterranean Oscillation (WeMO).

scholarly journals Trends in rainfall erosivity in NE Spain at annual, seasonal and daily scales, 1955–2006

2012 ◽  
Vol 16 (10) ◽  
pp. 3551-3559 ◽  
Author(s):  
M. Angulo-Martínez ◽  
S. Beguería
Keyword(s):  
Western Mediterranean ◽  
Rainfall Erosivity ◽  
Spatial And Temporal Variability ◽  
Rainfall Events ◽  
Atmospheric Teleconnection ◽  
Ebro Valley ◽  
The North ◽  
The North Atlantic Oscillation ◽  
Mediterranean Oscillation ◽  
Ne Spain

Abstract. Rainfall erosivity refers to the ability of precipitation to erode soil, and depends on characteristics such as its total volume, duration, and intensity and amount of energy released by raindrops. Despite the relevance of rainfall erosivity for soil degradation prevention, very few studies have addressed its spatial and temporal variability. In this study the time variation of rainfall erosivity in the Ebro Valley (NE Spain) is assessed for the period 1955–2006. The results show a general decrease in annual and seasonal rainfall erosivity, which is explained by a decrease of very intense rainfall events whilst the frequency of moderate and low events increased. This trend is related to prevailing positive conditions of the main atmospheric teleconnection indices affecting the West Mediterranean, i.e. the North Atlantic Oscillation (NAO), the Mediterranean Oscillation (MO) and the Western Mediterranean Oscillation (WeMO).

scholarly journals Non-stationary flood frequency analysis in continental Spanish rivers, using climate and reservoir indices as external covariates

2013 ◽  
Vol 17 (8) ◽  
pp. 3189-3203 ◽  
Author(s):  
J. López ◽  
F. Francés
Keyword(s):  
Frequency Analysis ◽  
Western Mediterranean ◽  
Flood Frequency ◽  
Additive Models ◽  
Stationary Time Series ◽  
Flood Frequency Analysis ◽  
Climate Indices ◽  
Flood Regime ◽  
Mediterranean Oscillation ◽  
The Impact

Abstract. Recent evidences of the impact of persistent modes of regional climate variability, coupled with the intensification of human activities, have led hydrologists to study flood regime without applying the hypothesis of stationarity. In this study, a framework for flood frequency analysis is developed on the basis of a tool that enables us to address the modelling of non-stationary time series, namely, the "generalized additive models for location, scale and shape" (GAMLSS). Two approaches to non-stationary modelling in GAMLSS were applied to the annual maximum flood records of 20 continental Spanish rivers. The results of the first approach, in which the parameters of the selected distributions were modelled as a function of time only, show the presence of clear non-stationarities in the flood regime. In a second approach, the parameters of the flood distributions are modelled as functions of climate indices (Arctic Oscillation, North Atlantic Oscillation, Mediterranean Oscillation and the Western Mediterranean Oscillation) and a reservoir index that is proposed in this paper. The results when incorporating external covariates in the study highlight the important role of interannual variability in low-frequency climate forcings when modelling the flood regime in continental Spanish rivers. Also, with this approach it is possible to properly introduce the impact on the flood regime of intensified reservoir regulation strategies. The inclusion of external covariates permits the use of these models as predictive tools. Finally, the application of non-stationary analysis shows that the differences between the non-stationary quantiles and their stationary equivalents may be important over long periods of time.

scholarly journals Non-stationary flood frequency analysis in continental Spanish rivers, using climate and reservoir indices as external covariates

2013 ◽  
Vol 10 (3) ◽  
pp. 3103-3142 ◽  
Author(s):  
J. López ◽  
F. Francés
Keyword(s):  
Frequency Analysis ◽  
Western Mediterranean ◽  
Flood Frequency ◽  
Additive Models ◽  
Stationary Time Series ◽  
Flood Frequency Analysis ◽  
Climate Indices ◽  
Flood Regime ◽  
Mediterranean Oscillation ◽  
The Impact

Abstract. Recent evidences of the impact of persistent modes of regional climate variability, coupled with the intensification of human activities, have led hydrologists to study flood regime without applying the hypothesis of stationarity. In this study, a framework for flood frequency analysis is developed on the basis of a tool that enables us to address the modelling of non-stationary time series, namely, the "generalized additive models for location, scale and shape" (GAMLSS). Two approaches to non-stationary modelling in GAMLSS were applied to the annual maximum flood records of 20 continental Spanish rivers. The results of the first approach, in which the parameters of the selected distributions were modeled as a function of time only, show the presence of clear non-stationarities in the flood regime. In a second approach, the parameters of the distributions are modeled as functions of climate indices (Arctic Oscillation, North Atlantic Oscillation, Mediterranean Oscillation and the Western Mediterranean Oscillation) and a reservoir index that is proposed in this paper. The results when incorporating external covariates in the study highlight the important role of interannual variability in low-frequency climate forcings when modelling the flood regime in continental Spanish rivers. Also, with this approach is possible to properly introduce the impact on the flood regime of intensified reservoir regulation strategies and to be used as predictive tools. Application of non-stationary analysis shows that the differences between the quantiles obtained and their stationary equivalents may be important over long periods of time.

scholarly journals Assimilation of wind data from airborne Doppler cloud-profiling radar in a kilometre-scale NWP system

2018 ◽  
Author(s):  
Mary Borderies ◽  
Olivier Caumont ◽  
Julien Delanoë ◽  
Véronique Ducrocq ◽  
Nadia Fourrié
Keyword(s):  
Positive Impact ◽  
Heavy Precipitation ◽  
Mediterranean Area ◽  
Western Mediterranean ◽  
Wind Data ◽  
Heavy Rainfall Event ◽  
Rain Gauges ◽  
The North ◽  
W Band ◽  
The Impact

Abstract. The article reports on the impact of the assimilation of wind vertical profile data in a kilometre-scale NWP system on predicting heavy precipitation events in the north-western Mediterranean area. The data collected in diverse conditions by the airborne W-band radar RASTA (Radar Airborne System Tool for Atmosphere) during a 45-day period are assimilated in the 3-h 3DVar assimilation system of AROME. The impact of the length of the assimilation window is investigated. The data assimilation experiments are performed for a heavy rainfall event, which occurred over south-eastern France on 26 September 2012 (IOP7a), and over a 45-day cycled period. During IOP7a, results indicate that the quality of the rainfall accumulation forecasts increases with the length of the assimilation window. By contrast, on the 45-day period, the best scores against rain gauges measurements are reached with a 1 hour assimilation window, which recommends to use observations with a small period centred on the assimilation time. The positive impact of the assimilation of RASTA wind data is particularly evidenced for the IOP7a case since results indicate an improvement in the predicted wind at short term ranges (2 hours and 3 hours) and in the 12-hour precipitation forecasts. However, on the 45-day cycled period, the comparison against other assimilated observations shows an overall neutral impact. Results are still encouraging since a slight positive improvement in the 6-, 9- and 12-hour precipitation forecasts of heavier rainfall was demonstrated.

Frontal variability and its impact on chlorophyll in the Arabian Sea

2020 ◽  
Author(s):  
Yuntao Wang ◽  
Wentao Ma ◽  
Feng Zhou ◽  
Chai Fei
Keyword(s):  
Arabian Sea ◽  
Coastal Upwelling ◽  
Cold Water ◽  
Southwest Monsoon ◽  
Ocean Dynamics ◽  
Ekman Transport ◽  
Spatial And Temporal Variability ◽  
Anomalous Field ◽  
The North ◽  
The Impact

<p>Sixteen years satellite observations are used to investigate the frontogenesis, frontal variability and its impact on chlorophyll in the Arabian Sea. Large frontal probability (FP) and high chlorophyll mainly happens near the coast, e.g., near Somalia and Oman, and its value generally decreases with offshore distance. An Empirical Orthogonal Function (EOF) is used to disentangle the spatial and temporal variability of front and chlorophyll. Prominent seasonal cycle of frontal activities is identified, peaking in summer when southwest wind prevails. The seasonality for chlorophyll is same with wind and front near Somalia, which largely impacted by monsoon. During summer, the southwest monsoon drives offshore Ekman transport and induces coastal upwelling. It transports subsurface cold water and nutrients to the surface layer, which generates fronts and enhances chlorophyll, respectively. The frontal activities can be used as an indicator to determine the chlorophyll level that high chlorophyll happens when frontal probability gets higher than 2%. At anomalous field, stronger wind can induce higher frontal activities and chlorophyll. The impact of wind on frontogenesis can extend 1,000km offshore and a simplified linear regression is applied to quantify their relationship. The variability of wind leads chlorophyll by lags increasing with distance, indicating a horizontal offshore transport of coastal water. In winter, the northeast wind is not upwelling favorable, thus the frontal activities and chlorophyll are greatly reduced off Somalia. During this period, large chlorophyll is found in the north off Oman because of mixing, thus its relationship with front is less pronounced. In the upwelling regions, fronts act as an intermedia process that connecting the wind forcing and responses of ecosystem. The frontal activities in Arabian Sea is fundamentally important to improve our understanding of monsoon related ocean dynamics.</p>

scholarly journals The Genome Sequence of the Octocoral Paramuricea clavata – A Key Resource To Study the Impact of Climate Change in the Mediterranean

2020 ◽  
Vol 10 (9) ◽  
pp. 2941-2952
Author(s):  
Jean-Baptiste Ledoux ◽  
Fernando Cruz ◽  
Jèssica Gómez-Garrido ◽  
Regina Antoni ◽  
Julie Blanc ◽  
...  
Keyword(s):  
Evolutionary Ecology ◽  
De Novo ◽  
Western Mediterranean ◽  
De Novo Genome Assembly ◽  
Protein Coding ◽  
The North ◽  
Paramuricea Clavata ◽  
The Mediterranean ◽  
Differential Responses ◽  
The Impact

Abstract The octocoral, Paramuricea clavata, is a habitat-forming anthozoan with a key ecological role in rocky benthic and biodiversity-rich communities in the Mediterranean and Eastern Atlantic. Shallow populations of P. clavata in the North-Western Mediterranean are severely affected by warming-induced mass mortality events (MMEs). These MMEs have differentially impacted individuals and populations of P. clavata (i.e., varied levels of tissue necrosis and mortality rates) over thousands of kilometers of coastal areas. The eco-evolutionary processes, including genetic factors, contributing to these differential responses remain to be characterized. Here, we sequenced a P. clavata individual with short and long read technologies, producing 169.98 Gb of Illumina paired-end and 3.55 Gb of Oxford Nanopore Technologies (ONT) reads. We obtained a de novo genome assembly accounting for 607 Mb in 64,145 scaffolds. The contig and scaffold N50s are 19.15 Kb and 23.92 Kb, respectively. Despite of the low contiguity of the assembly, its gene completeness is relatively high, including 75.8% complete and 9.4% fragmented genes out of the 978 metazoan genes contained in the metazoa_odb9 database. A total of 62,652 protein-coding genes have been annotated. This assembly is one of the few octocoral genomes currently available. This is undoubtedly a valuable resource for characterizing the genetic bases of the differential responses to thermal stress and for the identification of thermo-resistant individuals and populations. Overall, having the genome of P. clavata will facilitate studies of various aspects of its evolutionary ecology and elaboration of effective conservation plans such as active restoration to overcome the threats of global change.

scholarly journals Trans-pacific transport and evolution of aerosols: Evaluation of quasi global WRF-Chem simulation with multiple observations

2016 ◽  
Author(s):  
Zhiyuan Hu ◽  
Chun Zhao ◽  
Jianping Huang ◽  
L. Ruby Leung ◽  
Yun Qian ◽  
...  
Keyword(s):  
Rural Areas ◽  
Carbonaceous Aerosol ◽  
Spatial And Temporal Variability ◽  
Marine Aerosols ◽  
Global Simulation ◽  
Model Biases ◽  
The North ◽  
Multiple Observations ◽  
The Pacific ◽  
The Impact

Abstract. A fully coupled meteorology-chemistry model (WRF-Chem) has been configured to conduct quasi-global simulation for the 5 years of 2010–2014 and evaluated with multiple observation datasets for first time. The evaluation focuses on the simulation over the trans-Pacific transport region using various reanalysis and observational datasets for meteorological fields and aerosol properties. In general, precipitation and winds are well simulated by the model. The simulation captures the overall spatial and seasonal variability of satellite retrieved aerosol optical depth (AOD) and absorbing AOD (AAOD) over the Pacific that is determined by the outflows of pollutants and dust and the emissions of marine aerosols. The assessment of simulated extinction Angstrom exponent (EAE) indicates that the model generally reproduces the variability of aerosol size distributions as seen by satellites. In addition, the vertical profile of aerosol extinction and its seasonality over the Pacific that are dominated by marine aerosols near the surface and the outflow of pollutants and dust above 4 km are also well simulated. The difference between the simulation and satellite retrievals can be mainly attributed to model biases in estimating marine aerosol emissions as well as the satellite sampling and retrieval uncertainties. Compared with the surface measurements over the western U.S., the model reproduces the observed magnitude and seasonality of dust, sulfate, and nitrate surface concentrations, but significantly underestimates the peak surface concentrations of carbonaceous aerosol likely due to model biases in the spatial and temporal variability of biomass burning emissions and secondary organic aerosol (SOA) production. A sensitivity simulation shows that the trans-Pacific transported dust, sulfate, and nitrate can make significant contribution to surface concentrations over the rural areas of the western U.S., while the peaks of carbonaceous aerosol surface concentrations are dominated by the North American emissions. Both the retrievals and simulation show small interannual variability of aerosol characteristics for 2010–2014 averaged over three Pacific sub-regions. The evaluation in this study demonstrates that the WRF-Chem quasi global simulation can be used for investigating trans-Pacific transport of aerosols and providing reasonable inflow chemical boundaries for the western U.S. to further understand the impact of transported pollutants on the regional air quality and climate with high-resolution nested regional modeling.

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