scholarly journals Synoptic causes of torrential rainfall in South-eastern Spain (1941–2017)

2020 ◽  
Author(s):  
J. Martín-Vide ◽  
M.C. Moreno-García ◽  
J.A. López-Bustins
Keyword(s):  
High Altitude ◽  
Surface Pressure ◽  
Western Mediterranean ◽  
Teleconnection Pattern ◽  
Weather Station ◽  
Synoptic Classification ◽  
South Eastern ◽  
Torrential Rainfall ◽  
Mediterranean Oscillation ◽  
Cold Core

The weather types of 68 dates with torrential rainfall (≥200 mm/day) recorded at any weather station in the provinces of Alicante or Murcia during the period between 1941 and 2017 were determined using the Martín-Vide’s 1984 manual synoptic classification. Other relevant synoptic characteristics, as well as the surface pressure, and the value of the Western Mediterranean Oscillation index (WeMOi) on which those dates fell were also considered. The results show the high percentage of the Advection from the East with DANA (isolated high-altitude depression) or ‘gota fría’ type, which is present in more than 50% of the events, followed by the Trough type at 500 hPa and the Dynamic or Cold-core Low type, in the torrential rainfalls of South-eastern Spain. Except for the latter type, the average air pressure is close to or higher than normal. The WeMOi was negative for all events, which is consistent with the nature of this teleconnection pattern.

Torrential rainfall prediction: WeMOTool

2020 ◽  
Author(s):  
Laia Arbiol-Roca
Keyword(s):  
Iberian Peninsula ◽  
Surface Pressure ◽  
Significant Relationship ◽  
Western Mediterranean ◽  
Pressure Data ◽  
Predictive Tool ◽  
Rainfall Prediction ◽  
Gfs Model ◽  
Torrential Rainfall ◽  
Mediterranean Oscillation

<p>The Western Mediterranean Oscillation index (WeMOi) presents a statistically significant relationship with the pluviometric totals of the eastern façade of the Iberian Peninsula. Use of the WeMOi at daily resolution has proven to constitute a useful tool for helping to predict torrential rainfall episodes in the east of the peninsula. The present research attempts to determinate which atmospherics circulations defines the WeMOi phases. Also, the WeMOi research has focused on the prediction of it in order to configure itself as a predictive tool, the WeMOTool, for torrential rains associated, especially during the autumn months. The calculation of this index is made using the surface pressure data of the GFS model and is updated with the model outputs at 00h and 12h and up to 144h.</p>

scholarly journals Intra-annual variability of the Western Mediterranean Oscillation (WeMO) and occurrence of extreme torrential rainfall in Catalonia (NE Iberia)

2019 ◽  
Author(s):  
Joan Albert Lopez-Bustins ◽  
Laia Arbiol-Roca ◽  
Javier Martin-Vide ◽  
Antoni Barrera-Escoda ◽  
Marc Prohom
Keyword(s):  
Climate Change ◽  
Mediterranean Region ◽  
Western Mediterranean ◽  
Sensitive Area ◽  
Weather Extremes ◽  
Late Autumn ◽  
Annual Variability ◽  
Torrential Rainfall ◽  
Mediterranean Oscillation

Abstract. In previous studies the Western Mediterranean Oscillation index (WeMOi) at daily resolution has proven to constitute an effective tool for analysing the occurrence of episodes of torrential rainfall over eastern Spain. The Western Mediterranean region is therefore a very sensitive area, since climate change can enhance these weather extremes. In the present study we selected the extreme torrential episodes (≥ 200 mm in 24 hours) that took place in Catalonia (NE Iberia) during the 1951–2016 study period (66 years). We computed daily WeMOi values and constructed WeMOi calendars. Our principal results reveal the occurrence of 50 episodes (0.8 cases per year), mainly concentrated in the autumn months. We inferred a threshold of WeMOi ≤ −2 to define an extreme negative WeMO phase at daily resolution. Most of the 50 episodes (60 %) in the study area occurred on days presenting an extreme negative WeMOi value. Specifically, the most negative WeMOi values are detected in autumn, during the second 10-day period of October (11th–20th), coinciding with the highest frequency of extreme torrential events. On comparing the subperiods, we observed a statistically significant decrease in WeMOi values in all months, particularly in late October, and in November and December. No changes in the frequency of these extreme torrential episodes were observed between both subperiods; in contrast, a displacement of the episodes is detected from early to late autumn.

scholarly journals Torrential rainfall in northeast of the Iberian Peninsula: synoptic patterns and WeMO influence

2008 ◽  
Vol 2 (1) ◽  
pp. 99-105 ◽  
Author(s):  
J. Martin-Vide ◽  
A. Sanchez-Lorenzo ◽  
J. A. Lopez-Bustins ◽  
M. J. Cordobilla ◽  
A. Garcia-Manuel ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Principal Component ◽  
Western Mediterranean ◽  
Atmospheric Conditions ◽  
Synoptic Patterns ◽  
Daily Data ◽  
Circulation Patterns ◽  
Torrential Rainfall ◽  
Index Value ◽  
Mediterranean Oscillation

Abstract. This study presents a catalogue of synoptic patterns of torrential rainfall in northeast of the Iberian Peninsula (IP). These circulation patterns were obtained by applying a T-mode Principal Component Analysis (PCA) to a daily data grid (NCEP/NCAR reanalysis) at sea level pressure (SLP). The analysis made use of 304 days which recorded >100 mm in one or more stations in provinces of Barcelona, Girona and Tarragona (coastland area of Catalonia) throughout the 1950–2005 period. The catalogue comprises 7 circulation patterns showing a great variety of atmospheric conditions and seasonal or monthly distribution. Likewise, we computed the mean index value of the Western Mediterranean Oscillation index (WeMOi) for the synoptic patterns obtained by averaging all days grouped in each pattern. The results showed a clear association between the negative values of this teleconnection index and torrential rainfall in northeast of the IP. We therefore put forward the WeMO as an essential tool for forecasting heavy rainfall in northeast of Spain.

scholarly journals Synoptic Causes of Torrential Rainfall in the Balearic Islands (1941–2010)

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1035
Author(s):  
Miquel Grimalt-Gelabert ◽  
Gabriel Alomar-Garau ◽  
Javier Martin-Vide
Keyword(s):  
Mediterranean Basin ◽  
Western Mediterranean ◽  
Balearic Islands ◽  
Eastern Coast ◽  
Weather Station ◽  
Atmospheric Conditions ◽  
Common Occurrence ◽  
Torrential Rain ◽  
Western Mediterranean Basin ◽  
Torrential Rainfall

This article determines the atmospheric situation for the 53 days where any weather station in the Balearic Islands detected torrential rain (equal to or above 200 mm in a single day) during the period 1941–2010. To do this, the synoptic charts for each day were analysed, classifying them in accordance with the types established by Martín Vide (1984) and, in addition, through the automatic synoptic classifications from Jenkinson and Collison (1977). The analysis results demonstrate the importance of cyclonic situations over the Western Mediterranean Basin linked to favourable altitude configurations (earlier presence of cut-off lows—DANA—or troughs). These atmospheric conditions contrast with those that predominate in nearby Mediterranean areas, such as the south-eastern coast of the Iberian Peninsula. Days with torrential rain on the Iberian coastline tend to coincide with easterly advections—a less common occurrence in the Balearics.

scholarly journals Morphological variation in Leptorhynchos squamatus (Gnaphalieae: Asteraceae)

2002 ◽  
Vol 15 (2) ◽  
pp. 205 ◽  
Author(s):  
Christina Flann ◽  
Pauline Y. Ladiges ◽  
Neville G. Walsh
Keyword(s):  
High Altitude ◽  
Morphological Variation ◽  
Environmental Conditions ◽  
Leaf Size ◽  
Alpine Plants ◽  
The Other ◽  
Herbarium Specimens ◽  
South Eastern ◽  
Eastern Australia ◽  
Low Altitude

A study of morphological variation in Leptorhynchos squamatus (Labill.) Less. across its range in south-eastern Australia was undertaken to test the hypothesis that L. squamatus includes two taxa. Phenetic pattern analyses of both field-collected and herbarium specimens on the basis of morphology confirmed two major groups. Bract, cypsela, pappus bristle and leaf characters were particularly important in separating the two groups. The taxa are separated by altitude differences with one being a low-altitude plant found in many habitats and the other being a high-altitude taxon that is a major component of alpine meadows. Lowland plants have dark bract tips, fewer and wider pappus bristles than alpine plants, papillae on the cypselas and more linear leaves. A somewhat intermediate population from the Major Mitchell Plateau in the Grampians shows some alpine and some lowland characters but is included in the lowland taxon. Seeds from five populations (two alpine, two lowland and Major Mitchell) were germinated and plants grown for 18 weeks under four controlled sets of environmental conditions. The experiment showed that leaf size and some other characters are affected by environmental conditions, but that there are underlying genetic differences between the lowland and alpine forms. Leptorhynchos squamatus subsp. alpinus Flann is described here to accommodate the highland taxon.

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.

Speleothem δ13C record suggests enhanced spring/summer drought in south-eastern Spain between 9.7 and 7.8 ka – A circum-Western Mediterranean anomaly?

The Holocene ◽  
2019 ◽  
Vol 29 (7) ◽  
pp. 1113-1133 ◽  
Author(s):  
Alexander Budsky ◽  
Denis Scholz ◽  
Jasper A Wassenburg ◽  
Regina Mertz-Kraus ◽  
Christoph Spötl ◽  
...  
Keyword(s):  
Late Glacial ◽  
Western Mediterranean ◽  
Hadley Cell ◽  
Time Interval ◽  
Summer Drought ◽  
Vegetation Density ◽  
Strong Reduction ◽  
South Eastern ◽  
The North ◽  
Climate Records

South-eastern Spain is one of the driest regions in Europe and thus, prone to drought. Terrestrial climate records covering the late Glacial and Holocene from this area are sparse. Here, we present a flowstone record from Cueva Victoria, south-eastern Spain, which covers the late Glacial (15 ka) to the mid-Holocene (7 ka) including the Younger Dryas (YD). Between the onset of the Bølling/Allerød (B/A) and the early Holocene, flowstone δ18O values progressively decrease in accordance with sea-surface temperatures in the Alboran Sea, indicating an increase in precipitation in south-eastern Spain and a supra-regional signal of North Atlantic temperature change. At the same time, decreasing δ13C values suggest progressively increasing precipitation and vegetation density. This trend is interrupted by both colder and drier conditions during the YD. Between 9.7 ± 0.3 and 7.8 ± 0.2 ka, a large positive excursion of the δ13C values indicates a strong reduction in vegetation density, probably as a consequence of very dry spring/summer conditions. In combination with the continuously low speleothem δ18O values and a nearly unchanged growth rate, this suggests increased seasonality (i.e. drier spring/summer conditions, but not a strong reduction in annual precipitation). This is consistent with several other climate records from the Western Mediterranean region, showing that the Western Mediterranean realm (Spain, Italy) experienced pronounced spring/summer drought during this time interval. Interestingly, the timing of this dry period coincided with the African Humid Period. This may be part of a teleconnection with the North African Monsoon via the Hadley cell circulation.

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