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Benhamrouche Aziz Martin-Vide Javier Pham Quoc Bao Kouachi Mostefa E. Moreno-Garcia M. Carmen 《Theoretical and Applied Climatology》2022,147(1-2):37-45
Theoretical and Applied Climatology - Empirical frequency distribution of daily precipitation amounts can be fitted by a negative exponential distribution, because anywhere there are many small... 相似文献
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We determined the weather type, according to the Jenkinson and Collison procedure, of the 22 646 days in the 1948-2009 period for the western Mediterranean basin. The analysis is based upon the surface pressure values of the NCEP/NCAR reanalysis, for a grid of nine points with extreme vertices at 45º N, 5º W and 35º N, 15º E, which provides a broad synoptic catalogue for this region. We analyzed the trends of the types and their different groupings during the same period. The most frequent type is U (undetermined), with an annual average of approximately 100 days (99.4, 27.2%), followed by type A (anticyclone), with 75.5 days/ year (20.7%), and C (depression), with 67.8 days/year (18.6%). The high frequency of type U is due to the habitual pressure of baric fields with a low gradient over Mediterranean waters in the warm half of the year. According to their directions, the types from the west are the most frequent and those from the south, the least. The monthly regime of the most frequent types and groupings is quite regular; type C groups, as well as advective and cyclonic curvature groups, present summertime minima and maxima in the cold half of the year, whereas the opposite occurs with types U and A. The main statistically significant annual trends in the 1948-2009 period involve a decrease in type A (–4.19 days/decade, that is, –29.0%) and an increase in type U, the cyclonic types and those presenting an easterly component. On comparing the 31-yr sub-periods 1948-1978 and 1979-2009, the tendencies of A and U were confirmed, and increases can generally be seen in the types presenting an easterly component and a decrease in those with a westerly component. The variation in type A ranged from 2490 days in the first sub-period to 2192 in the second one (p = 0.000), mainly concentrated in summer and autumn. This evident reduction of type A coincides, paradoxically, with an increase in the sea surface pressure variable (+0.31 hPa/decade) throughout the 62 years of analysis. The negative trend found in type A differs from the results of some studies. The different analysis periods, the different scales or areas of study and the variety of methods used to determine the weather types can account for the fact that these results are discordant. Moreover, warming over the last few decades in the waters of the western Mediterranean basin, as well as the clearly cyclogenetic character of the gulfs of Lion and Genoa, might account for the decrease in type A and the increase in the cyclonic curvature types. 相似文献
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Qinglong You Shichang Kang Wolfgang-Albert Flügel Arturo Sanchez-Lorenzo Yuping Yan Jie Huang Javier Martin-Vide 《Theoretical and Applied Climatology》2010,101(3-4):445-457
The Tibetan Plateau (TP) with an average elevation of over 4,000 m asl is the highest and most extensive highland in the world. We used monthly mean sunshine duration from the Chinese Meteorological Administration to examine the spatial and temporal variability of sunshine duration at 71 stations with elevations above 2,000 m asl in the eastern and central TP during the 1961–2005 period. The temporal evolution of the mean annual sunshine duration series shows a significant increase from 1961 to 1982 at a rate of 49.8 h/decade, followed by a decrease from 1983 to 2005 at a rate of ?65.1 h/decade, with an overall significant decrease at a rate of ?20.6 h/decade during the whole 1961–2005 period, which is mainly due to the summer and spring seasons. This confirms the evidence that sunshine duration in the TP ranges from brightening to dimming in accordance with sunshine duration trends in the rest of China. The surface solar radiation downwards from ERA-40 reanalysis data in the same region confirms the brightening/dimming phenomenon shown by the sunshine duration before/after the 1980s. Otherwise, additional climatic variables such as low cloud amount, total cloud amount, precipitation, relative humidity and water vapor pressure, in most cases, exhibit significant negative correlation with sunshine duration in the TP on an annual and seasonal basis before and after 1982, respectively. The trends of these variables suggest that changes in some of them might be related to the brightening and dimming detected with the use of sunshine duration measurements over the TP. We also hypothesize that the impact of anthropogenic aerosols upon the climatic variables analyzed cannot be rejected, especially in the significant increase in low cloud cover since approximately 1980. 相似文献
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Historical documentation describing events on the Mediterranean coast of the Iberian Peninsula allows us to reconstruct the record of catastrophic floods. Through this information, it is possible to identify and to date three climatic oscillations within the so-called Little Ice Age: 1570–1630, 1760–1800 and 1830–1870, which coincide with advances in some Alps glaciers. 相似文献
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Summary A methodology developed for automatic classification of Objective Synoptic Processes (OSP) and its application to the study
of the mesoscale atmospheric circulatory patterns associated with them is described. The classification was based on the analysis
of the evolution of surface pressure and geopotencial height at 500 hPa during three days. An iterative procedure results
in an objective grouping of the main configurations describing different large-scale situations. This routine has been applied
over an appropriate domain covering the Iberian Peninsula to obtain OSPs in the region for the two month period July–August,
using daily synoptic maps for years 1990 to 1999 (a total of 7304 surface and 500 hPa synoptic maps have been used in the
analysis). Finally, for a characteristic day for two of the OSPs obtained, a mesoscale meteorological model (TAPM) has been
run at high resolution for the region of Catalonia, Northeastern Spain, in order to describe the local atmospheric circulatory
patterns associated with a given large-scale situation. Results show that the complex orography modifies the large-scale forcings
resulting in wind fields with a very important horizontal variability, significant daily cycle, and specific local features
related to orographic elements, which the model was able to incorporate due to the highly-resolved orography used. 相似文献
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This study investigates the connections between climate fluctuations and sardine and anchovy production in the NW Mediterranean, taking the Western Mediterranean Oscillation index (WeMOi) as an indicator of climate variability. The basic working hypothesis is that sardine and anchovy productivity is influenced by the WeMOi, a proxy for the local environmental conditions such as sea surface temperature (SST) and river runoff. Sardine and anchovy landings (1974–2009) in the Catalan Coast and landings per unit of effort (LPUE) were used as proxy for recruitment. The results demonstrated a clear link between climate fluctuations and sardine and anchovy production. Positive WeMOi values were significantly correlated with low SST, high river runoff and high LPUE, that is, with better-than-average recruitment of sardine and anchovy. Conversely, negative WeMOi values were associated with high SST, low river runoff and low LPUE. During the negative WeMOi phases (such as that at the end of the analyzed period), environmental conditions are unfavourable for the overall biological productivity in the NW Mediterranean and would decrease the survival, growth, condition and reproduction of sardine and anchovy during their life cycle. Despite the evidences on the appropriateness of the NAOi as an indicator of the climate in Europe and its impact on some biological variables, we suggest that using a regional index, such as the WeMOi, can provide a more accurate representation of the environmental conditions affecting small pelagic fish production in the NW Mediterranean. 相似文献
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The spatial–temporal patterns of cloud-to-ground (CG) lightning covering the period 2010–2015 over the northwest Iberian Peninsula were investigated. The analysis conducted employed three main methods: the circulation weather types developed by Jenkinson and Collison, the fit of a generalized additive model (GAM) for geographic variables, and the use of a concentration index for the ratio of lightning strikes and thunderstorm days. The main activity in the summer months can be attributed to situations with eastern or anticyclonic flow due to convection by insolation. In winter, lightning proves to have a frontal origin and is mainly associated with western or cyclonic flow situations which occur with advections of air masses of maritime origin. The largest number of CG discharges occurs under eastern flow and their hybrids with anticyclonic situations. Thunderstorms with greater CG lightning activity, highlighted by a higher concentration index, are located in areas with a higher density of lightning strikes, above all in mountainous areas away from the sea. The modeling of lightning density with geographic variables shows the positive influence of altitude and, particularly, distance to the sea, with nonlinear relationships due to the complex orography of the region. Likewise, areas with convex topography receive more lightning strikes than concave ones, a relation which has been demonstrated for the first time from a GAM. 相似文献
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Carme?Farnell Tomeu?RigoEmail authorView author&#;s OrcID profile Javier?Martin-Vide 《Theoretical and Applied Climatology》2018,131(1-2):133-151
There are primarily two ways of estimating hail size: the first is the direct interpolation of point observations, and the second is the transformation of remote sensing fields into measurements of hail properties. Both techniques have advantages and limitations as regards generating the resultant map of hail damage. This paper presents a new methodology that combines the above mentioned techniques in an attempt to minimise the limitations and take advantage of the benefits of interpolation and the use of remote sensing data. The methodology was tested for several episodes with good results being obtained for the estimation of hail size at practically all the points analysed. The study area presents a large database of hail episodes, and for this reason, it constitutes an optimal test bench. 相似文献
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Dario Camuffo Caterina Secco Peter Brimblecombe Javier Martin-Vide 《Climatic change》2000,46(1-2):209-223
Data regarding the frequency andoccurrence of sea storms in the Adriatic Sea and theWestern Mediterranean during the last millennium havebeen extracted from historical written sources. TheAdriatic Sea shows two anomalous periods of high stormfrequency: the first half of the 1500s and the secondhalf of the 1700s. In the 1500s the storms were morefrequent in autumn, while in the late 1700s theyoccurred at high frequency in winter. In the WesternMediterranean, storms had a higher frequency in thefirst half of the 1600s, with two lesser periods ofhigh frequency in the 1400s and at the end of the1700s. Although both records show a maximum frequencyof sea storms during the Spörer Minimum(1416–1534) of solar activity, sunspot series yieldno, or poor, correlation during the other periods oflowest activity, i.e., Oort Minimum (1010–1090), WolfMinimum (1282–1342), and Maunder Minimum (1645–1715),suggesting that a teleconnection between sea stormsand sunspots is improbable or masked in this region.No teleconnection was found either between the ElNiño-Southern Oscillation (ENSO) and surgesflooding Venice or the Western Mediterranean storms orbetween Venice surges and the Northern AtlanticOscillation (NAO). 相似文献
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