scholarly journals Mediterranean depression characteristics related to precipitation occurrence in Crete, Greece

2014 ◽  
Vol 2 (9) ◽  
pp. 6107-6139 ◽  
Author(s):  
V. Iordanidou ◽  
A. G. Koutroulis ◽  
I. K. Tsanis
Keyword(s):  
Daily Precipitation ◽  
Morphological Characteristics ◽  
Variable Intensity ◽  
Weather Forecasts ◽  
Precipitation Occurrence ◽  
Seasonal Characteristics ◽  
Crete Island ◽  
Daily Precipitation Data ◽  
Ms Scheme ◽  
Precipitation Events

Abstract. The characteristics of the cyclone tracks and circulation patterns that caused precipitation events of variable intensity for the period 1979–2011 over the island of Crete are presented. The dataset usedfor cyclone identification, is the 0.5 x 0.5, 30 years European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim mean sea-level pressure. Their characteristics are extracted with the aid of Melbourne University algorithm (MS scheme). Daily precipitation data from a dense gauging network over the island of Crete is also used for the classification of the precipitation events in terms of intensity. Daily precipitation intensity is classified in three severity categories, and the associated cyclones are filtered according to their distance from Crete Island. The atmospheric systems are further investigated both seasonally and annually for their position relative to Crete and morphological characteristics such as intensity and radius. Generally, it was found that cyclones affecting Crete most frequently approach from northwest and southwest directions and the actual cyclone centers associated with precipitation events are usually located in northwest and southeast positions relative to Crete domain. Precipitation increase is observed in parallel with cyclone pressure decrease as well as cyclone intensity, depth, radius and propagation velocity increase. Specific seasonal characteristics such as lower pressures and cyclone radius can be detected in spring in contrast to winter and autumn precipitation events. The examination of the relation between cyclone characteristics and precipitation occurrence provides improved understanding of the complex hydro-meteorological conditions and therefore valuable hydrologic information related to forecasting potential and management of the resources and the extremes.

scholarly journals Mediterranean cyclone characteristics related to precipitation occurrence in Crete, Greece

2015 ◽  
Vol 15 (8) ◽  
pp. 1807-1819 ◽  
Author(s):  
V. Iordanidou ◽  
A. G. Koutroulis ◽  
I. K. Tsanis
Keyword(s):  
Propagation Velocity ◽  
Daily Precipitation ◽  
Variable Intensity ◽  
Data Set ◽  
Precipitation Occurrence ◽  
Crete Island ◽  
Daily Precipitation Data ◽  
Cyclone Tracks ◽  
Western Side ◽  
Precipitation Events

Abstract. The characteristics of the cyclone tracks that caused precipitation events of variable intensity for the period 1979–2011 over the island of Crete are presented. The data set used for cyclone identification is the 0.5° × 0.5°, 30 years European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim mean sea-level pressure. Cyclone characteristics are calculated with the aid of the Melbourne University algorithm (MS scheme). Daily precipitation data from a dense gauging network over the island of Crete are also used for the classification of the precipitation events in terms of rain accumulation (intensity). Daily precipitation is classified in three categories and the associated cyclones are chosen according to their distance from Crete island. The seasonal and annual cycle of the physical characteristics of the cyclone tracks are investigated with respect to the cyclones' relative position to the island of Crete. It was found that cyclones affecting Crete most frequently approach from the western side of the island and the actual cyclone centers associated with precipitation events are usually located northwest and southeast of the Crete domain. Cyclone-induced rainfall increases in function to cyclones' depth, radius and propagation velocity increase as well as cyclones' pressure decrease. Spring cyclones that affect Crete with rainfall present lower pressures and higher cyclone propagation velocity in contrast to the ones associated with winter and autumn precipitation events. The examination of the relation between cyclone characteristics and precipitation occurrence provides valuable information related to forecasting potential and management of the water resources and the rainfall extremes.

scholarly journals Annual and Seasonal Precipitation and Their Extremes over the Tibetan Plateau and Its Surroundings in 1963–2015

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 620
Author(s):  
Jin Ding ◽  
Lan Cuo ◽  
Yongxin Zhang ◽  
Cunjie Zhang ◽  
Liqiao Liang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Extreme Precipitation ◽  
Daily Precipitation ◽  
The Tibetan Plateau ◽  
Opposite Pattern ◽  
Westerly Jet ◽  
Extreme Precipitation Events ◽  
Daily Precipitation Data ◽  
Moisture Transports ◽  
Precipitation Events

Based on daily precipitation data from 115 climate stations, seasonal and annual precipitation and their extremes over the Tibetan Plateau and its surroundings (TPS) in 1963–2015 are investigated. There exists a clear southeast-northwest gradient in precipitation and extreme daily precipitation but an opposite pattern for the consecutive dry days (CDDs). The wet southeast is trending dry while the dry center and northwest are trending wet in 1963–2015. Correspondingly, there is a drying tendency over the wet basins in the southeast and a wetting tendency over the dry and semi-dry basins in the center and northwest in summer, which will affect the water resources in the corresponding areas. The increase (decrease) in precipitation tends to correspond to the increase (decrease) in maximum daily precipitation but the decrease (increase) in CDDs. Extreme precipitation events with 20-year, 50-year, 100-year, and 200-year recurrence occurred frequently in the past decades especially in the 1980s. The greatest extreme precipitation events tend to occur after the late 1990s and in the southeastern TPS. The ERA5 reanalysis and climate system indices reveal that (1) decreased moisture transports to the southeast in summer due to the weakening of the summer monsoons and the East Asian westerly jet; (2) increased moisture transports to the center in winter due to the strengthening of the winter westerly jet and north Atlantic oscillation; and (3) decreased instability over the southeast thus suppressing precipitation and increased instability over the northwest thus promoting precipitation. All these are conducive to the drying trends in the southeast and the wetting trends in the center.

scholarly journals CHARAKTERYSTYKA OPADÓW ATMOSFERYCZNYCH W GORZOWIE WIELKOPOLSKIM W LATACH 1951–2016

1970 ◽  
pp. 133-149
Author(s):  
KATARZYNA SZYGA-PLUTA ◽  
DOMINIKA WOJTKOWIAK
Keyword(s):  
Extreme Precipitation ◽  
Daily Precipitation ◽  
Precipitation Data ◽  
Atmospheric Front ◽  
Precipitation Occurrence ◽  
Daily Precipitation Data ◽  
Synoptic Conditions ◽  
Average Precipitation ◽  
Research Period

The purpose of the work is to characterize the precipitation occurrence and the synoptic conditions of the extreme cases in Gorzów Wielkopolski. In the paper the daily precipitation data from IMGW-PIB for Gorzów Wielkopolski station in years 1951–2016 were used. The average monthly, annual and seasonal sums were calculated and the intensity of precipitation was analyzed. Days without any precipitation were also included. Special attention was paid to extreme precipitation cases and their synoptic conditions. The average precipitation in the research period was 547,1 mm. On average, as much as 80% during the year were days with very low (0.1–1.0 mm) and low (1.1–5.0 mm) precipitation, and 13% with moderate (5.1–10.0 mm). Extreme daily precipitation totals in Gorzów Wielkopolski (95th percentile) occur mainly in summer and spring. They are associated with the transition of the atmospheric front or with the development of convection over heated land.

scholarly journals Identifying and correcting biases in localized downscaling estimates of daily precipitation return values

2021 ◽  
Vol 169 (3-4) ◽  
Author(s):  
Mark D. Risser ◽  
Daniel R. Feldman ◽  
Michael F. Wehner ◽  
David W. Pierce ◽  
Jeffrey R. Arnold
Keyword(s):  
Observational Data ◽  
Extreme Precipitation ◽  
Daily Precipitation ◽  
Time Of Day ◽  
Economic Damage ◽  
Data Set ◽  
Extreme Precipitation Events ◽  
Daily Precipitation Data ◽  
Precipitation Events ◽  
Made In

AbstractExtreme precipitation events are a major cause of economic damage and disruption, and need to be addressed for increasing resilience to a changing climate, particularly at the local scale. Practitioners typically want to understand local changes at spatial scales much smaller than the native resolution of most Global Climate Models, for which downscaling techniques are used to translate planetary-to-regional scale change information to local scales. However, users of statistically downscaled outputs should be aware that how the observational data used to train the statistical models is constructed determines key properties of the downscaled solutions. Specifically for one such downscaling approach, when considering seasonal return values of extreme daily precipitation, we find that the Localized Constructed Analogs (LOCA) method produces a significant low bias in return values due to choices made in building the observational data set used to train LOCA. The LOCA low biases in daily extremes are consistent across event extremity, but do not degrade the overall performance of LOCA-derived changes in extreme daily precipitation. We show that the low (negative) bias in daily extremes is a function of a time-of-day adjustment applied to the training data and the manner of gridding daily precipitation data. The effects of these choices are likely to affect other downscaling methods trained with observations made in the same way. The results developed here show that efforts to improve resilience at the local level using extreme precipitation projections can benefit from using products specifically created to properly capture the statistics of extreme daily precipitation events.

scholarly journals Chains of Spatial and Temporal Precipitation Occurrence Predictability Across the Continental U.S.

2021 ◽  
Vol 3 ◽  
Author(s):  
Allison Goodwell ◽  
Ritzwi Chapagain
Keyword(s):  
Information Sources ◽  
Daily Precipitation ◽  
Seasonal Patterns ◽  
Grid Cells ◽  
Precipitation Occurrence ◽  
Temporal Properties ◽  
Daily Precipitation Data ◽  
Different Seasons ◽  
Original Cell ◽  
Chain Lengths

Both spatial and temporal information sources contribute to the predictability of precipitation occurrence at a given location. These sources, and the level of predictability they provide, are relevant to forecasting and understanding precipitation processes at different time scales. We use information theory-based measures to construct connected “chains of influence” of spatial extents and timescales of precipitation occurrence predictability across the continental U.S, based on gridded daily precipitation data. These regions can also be thought of as “footprints” or regions where precipitation states tend to be most synchronized. We compute these chains of precipitation influence for grid cells in the continental US, and study metrics regarding their lengths, extents, and curvature for different seasons. We find distinct geographic and seasonal patterns, particularly longer chain lengths during the summer that are indicative of larger spatial extents for storms. While synchronous, or instantaneous, relationships are strongest for grid cells in the same region, lagged relationships arise as chains reach areas farther from the original cell. While this study focuses on precipitation occurrence predictability given only information about precipitation, it could be extended to study spatial and temporal properties of other driving factors.

Statistical Characteristics of Daily Precipitation: Comparisons of Gridded and Point Datasets

2008 ◽  
Vol 47 (9) ◽  
pp. 2468-2476 ◽  
Author(s):  
Leslie A. Ensor ◽  
Scott M. Robeson
Keyword(s):  
Daily Precipitation ◽  
Heavy Precipitation ◽  
Rain Gauge ◽  
Statistical Characteristics ◽  
Precipitation Data ◽  
Spatial Coverage ◽  
Daily Precipitation Data ◽  
Precipitation Total ◽  
Grid Points ◽  
Precipitation Events

Abstract Gridding of daily precipitation data alleviates many of the limitations of data that are derived from point observations, such as problems associated with missing data and the lack of spatial coverage. As a result, gridded precipitation data can be valuable for applied climatological research and monitoring, but they too have limitations. To understand the limitations of gridded data more fully (especially when they are used as surrogates for station data), annual precipitation total, rain-day frequency, and annual maxima are calculated and compared for five Midwestern grid points from the Climate Prediction Center’s Unified Rain Gauge Dataset (URD) and those of its nearest (rain gauge) station. To further examine differences between the two datasets, return periods of daily precipitation were calculated over a region encompassing Illinois and Indiana. These analyses reveal that the gridding process used to create the URD produced nearly the same annual totals as the rain gauge data; however, the gridding significantly increased the frequency of low-precipitation events while greatly reducing the frequency of heavy-precipitation events. Extreme precipitation values also were greatly reduced in the gridded precipitation data. While smoothing nearly always occurs when data are gridded, the gridding of discrete variables such as daily precipitation can produce datasets with statistical characteristics that are very different from those of the original observations.

scholarly journals EVALUATION OF TRMM-3B42V7 AND PERSIANN-CDR DAILY-PRECIPITATION PRODUCTS FOR THE SOUTHERN SLOPES OF ALBORZ MOUNTAINS, IRAN

2019 ◽  
Vol XLII-4/W18 ◽  
pp. 1163-1167
Author(s):  
S. Khalighi-Sigaroodi ◽  
E. Ghaljaee ◽  
A. Moghaddam Nia ◽  
A. Malekian ◽  
F. Zhang
Keyword(s):  
Daily Precipitation ◽  
Recognition Rate ◽  
Precipitation Data ◽  
Study Region ◽  
Satellite Precipitation ◽  
Rain Gauges ◽  
Daily Precipitation Data ◽  
Significant Difference ◽  
Precipitation Events

Abstract. The density of rain gauges in many regions is lower than standard. Therefore, there are no precise estimates of precipitation in such regions. Today the use of satellite data to overcome this deficiency is increasing day to day. Unfortunately, the results from different satellite products also show a significant difference. Hence, their evaluation and validation are very important. The main objective of this study is to investigate the accuracy of the daily precipitation data of TRMM-3B42 V7 and PERSIANN-CDR satellites under a case study in the southern slopes of Alborz mountains, Iran. For this purpose, satellite precipitation data were compared with ground measured precipitation data of 12 synoptic stations over a 15- year period. The statistical criteria of MAE, RMSE, and Bias were used to assess error and the statistical indices of POD, FAR, and CSI was used to evaluate the recognition rate of occurrence or non-occurrence of precipitation. The results showed that there is a low correlation between satellite precipitation data and ground measured precipitation data, and the lowest and the highest values of correlation coefficient are from 0.228 to 0.402 for TRMM and from 0.047 to 0.427 for PERSIANN, respectively. However, there is a theoretical consensus on other assessment parameters, so that TRMM data is preferable in terms of the amount of data bias and the False Alarm Ratio (FAR) and PERSIANN data is superior in terms of RMSE, POD, and CSI. Also, it seems that in the study region, both of TRMM and PERSIANN have overestimated the number of daily precipitation events, so that the number of daily precipitation events was estimated about 125% and 200% of ground stations by TRMM and PERSIANN, respectively.

scholarly journals Identifying and Correcting Biases in Localized Downscaling Estimates of Daily Precipitation Return Values

2021 ◽  
Author(s):  
Mark Risser ◽  
Daniel Feldman ◽  
Michael Wehner ◽  
David Pierce ◽  
Jeff Arnold
Keyword(s):  
Observational Data ◽  
Extreme Precipitation ◽  
Daily Precipitation ◽  
Time Of Day ◽  
Economic Damage ◽  
Data Set ◽  
Extreme Precipitation Events ◽  
Daily Precipitation Data ◽  
Precipitation Events ◽  
Made In

Abstract Extreme precipitation events are a major cause of economic damage and disruption, and need to be addressed for increasing resilience to a changing climate, particularly at the local scale. Practitioners typically want to understand local changes at spatial scales much smaller than the native resolution of most Global Climate Models, for which down scaling techniques are used to translate planetary-to-regional scale change information to local scales. However, users of statistically downscaled outputs should be aware that how the observational data used to train the statistical models is constructed determines key properties of the downscaled solutions. Specifically for one such downscaling approach, when considering seasonal return values of extreme daily precipitation, we find that the Localized Constructed Analogs (LOCA) method produces a significant low bias in return values due to choices made in building the observational data set used to train LOCA. The LOCA low biases in daily extremes are consistent across event extremity, but do not degrade the over all performance of LOCA-derived changes in extreme daily precipitation. We show that the low bias in daily extremes is a function of a time-of-day adjustment applied to the training data and the manner of gridding daily precipitation data. The effects of these choices are likely to affect other downscaling methods trained with observations made in the same way. The results developed here show that efforts to improve resilience at the local level using extreme precipitation projections can benefit from using products specifically created to properly capture the statistics of extreme daily precipitation events.

scholarly journals ENSO and Wintertime Extreme Precipitation Events over the Contiguous United States

2008 ◽  
Vol 21 (1) ◽  
pp. 22-39 ◽  
Author(s):  
Siegfried D. Schubert ◽  
Yehui Chang ◽  
Max J. Suarez ◽  
Philip J. Pegion
Keyword(s):  
United States ◽  
West Coast ◽  
Extreme Precipitation ◽  
East Coast ◽  
Daily Precipitation ◽  
Precipitation Variability ◽  
The West ◽  
Extreme Precipitation Events ◽  
The Impact ◽  
Precipitation Events

Abstract In this study the authors examine the impact of El Niño–Southern Oscillation (ENSO) on precipitation events over the continental United States using 49 winters (1949/50–1997/98) of daily precipitation observations and NCEP–NCAR reanalyses. The results are compared with those from an ensemble of nine atmospheric general circulation model (AGCM) simulations forced with observed SST for the same time period. Empirical orthogonal functions (EOFs) of the daily precipitation fields together with compositing techniques are used to identify and characterize the weather systems that dominate the winter precipitation variability. The time series of the principal components (PCs) associated with the leading EOFs are analyzed using generalized extreme value (GEV) distributions to quantify the impact of ENSO on the intensity of extreme precipitation events. The six leading EOFs of the observations are associated with major winter storm systems and account for more than 50% of the daily precipitation variability along the West Coast and over much of the eastern part of the country. Two of the leading EOFs (designated GC for Gulf Coast and EC for East Coast) together represent cyclones that develop in the Gulf of Mexico and occasionally move and/or redevelop along the East Coast producing large amounts of precipitation over much of the southern and eastern United States. Three of the leading EOFs represent storms that hit different sections of the West Coast (designated SW for Southwest coast, WC for the central West Coast, and NW for northwest coast), while another represents storms that affect the Midwest (designated by MW). The winter maxima of several of the leading PCs are significantly impacted by ENSO such that extreme GC, EC, and SW storms that occur on average only once every 20 years (20-yr storms) would occur on average in half that time under sustained El Niño conditions. In contrast, under La Niña conditions, 20-yr GC and EC storms would occur on average about once in 30 years, while there is little impact of La Niña on the intensity of the SW storms. The leading EOFs from the model simulations and their connections to ENSO are for the most part quite realistic. The model, in particular, does very well in simulating the impact of ENSO on the intensity of EC and GC storms. The main model discrepancies are the lack of SW storms and an overall underestimate of the daily precipitation variance.

Sign in / Sign up

Export Citation Format

Share Document