Daily Precipitation Concentration Research Articles

Assessing precipitation concentration in the Amazon basin from different satellite‐based data sets

Daily precipitation concentration in the Amazon basin (AB) is characterized using concentration index (CI), which is computed from HYBAM Observed Precipitation (HOP) data set, for 1980–2009 period. The ability of four satellite precipitation data sets (TMPA V7, TMPA RT, CMORPH and PERSIANN) to estimate CI is evaluated for 2001–2009 period. Our findings provide new information about the spatial irregularity of daily rainfall distribution over the AB. In addition, the spatial distribution of CI values is not completely explained by rainfall seasonality, which highlights the influence of different weather systems over the AB. The results of rainfall concentration indicate that the distribution of daily rainfall is more regular over northwest (northern Peru) and central Andes. Conversely, Roraima region and a large area of Bolivian Amazon register the highest irregularity in the daily rainfall. Bolivian Amazon also represents regions where the large percentage of total rainfall arises from extreme events (>90th percentile). Heavy rainfall episodes over Roraima region are induced by humidity influx come from Caribbean region, while heavy rainfall events over Bolivian Amazon and Andes region are induced by the northwards propagation of cold and dry air along both sides of Andes Mountains, but only propagate in all tropospheric levels for the Andes. The results also show that PERSIANN and TMPA7 data sets better estimates the daily precipitation concentration for whole AB, but with a relative error 8%. CI estimated from satellites does not agree well with HOP over the Andes and northern Peruvian Amazon. On the other hand, the temporal variability of CI can partly be detected using CMORPH and TMPAV7 data sets over the Peruvian Andes, and central and southern Brazil. Errors in CI estimating might be related to inaccurate estimation of daily rainfall. Finally, we conclude that satellite‐based precipitation data sets are useful for analysing rainfall concentration in some regions of AB.

Characterizing the properties of daily precipitation concentration in Amur River Basin of northeast China

The Amur River Basin is one of the most sensitive areas to the effects of climate change. In this study, spatial and temporal analysis of concentration index over the Amur River Basin in northeast China was presented. Precipitation data from 71 meteorological stations for the time series 1980-2018 on daily scale was employed in the study. The results indicated that precipitation events of low-intensity accounted for 28.59 % of rainy days, however, the proportion of rain amount was 1.33 %. On the contrary, high-and very high-intensity events accounted for 40.34 % of rainy days and as high as 90.53 % of annual precipitation amount. Precipitation concentration explain the cause of why some regions are prone to be influenced by high intensity precipitation events, spatial distribution of different intensities can be partly interpreted by daily rainfall heterogeneity and regional geomorphology. Furthermore, a significant change toward a stronger precipitation concentration was demonstrated over some regions, and this need concern from the administration.

Daily Precipitation Concentration Index for Krishna Basin

Daily Precipitation Concentration Index for Krishna Basin

Trends of daily precipitation concentration in Central-Southern Chile

The spatial and temporal variability of daily precipitation in Central-Southern Chile (~30–46°S), considering 176 meteorological stations for the period of 1965–2015, was analysed by mean of the concentration index (CI). The CI was calculated for the complete period, for the wet season and year-to-year, for each meteorological station. In addition, the trends were computed for the whole period by locations and by moving windows for the complete territory. The CI values range from 0.502 to 0.755, agreeing with previous works in the Mediterranean area and marine west coast climates. Linear correlations have been established between both year and wet season CI values with geographical factors, such as latitude, longitude and elevation. These correlations are statistically significant for the yearly CI with latitude and longitude, with −0.38 and − 0.39 Pearson's r values respectively (p-values lower than 0.001). However, the semiarid climates in Chile do not show the same behaviour as those presented in other regions of the world. The trends show an increase in the concentration of the whole series (mainly in the marine west coast climates) within the period between 1976 and 1994 with higher CI values, linked to the warm phase of the Pacific Decadal Oscillation.

Spatial analysis of daily precipitation concentration in Puerto Rico

The present study analyzes spatial patterns of precipitation Concentration Index (CI) in Puerto Rico considering the daily precipitation data of 20 precipitation-gauging stations during 1971–2010. The South and East interior parts of Puerto Rico are characterized by higher CI and the West and North-West parts show lower CI. The annual CI and the rainy season CI show a gradient from South-East to North-West and the dry season CI shows a gradient from South to North. Another difference between the rainy season CI and dry season CI is that the former shows the lowest values of CI while the latter shows the highest values of CI. The different types of seasonal precipitation seem to play a major role on the spatial CI distribution. However, the local relief plays a major role in the spatial patterns due to the effect of the air circulation by the mountains. These findings can contribute to basin-scale water resource management (flooding, soil erosion, etc.) and conservation of the ecological environment.

Distribución espacial del índice de concentración de precipitación diaria en los andes centrales peruanos: valle del río Mantaro

Los altos porcentajes de concentración de precipitación diaria en pocos días, pueden incrementar el potencial de erosión, inestabilidad de laderas y riesgo de inundaciones, siendo estos problemas comunes en el Perú, por lo que es importante el conocimiento acerca de la precipitación a nivel diario. En este articulo, se ha llevado a cabo una investigación acerca de los patrones espaciales y temporales de la concentración de precipitación diaria en los andes centrales del Perú, mediante el índice de concentración (IC), que evalúa la variación de la valoración de precipitación diaria, la contribución de grandes lluvias a la cantidad total presentada. El índice es aplicado a una curva exponencial como Y = aX exp(bX ) , el cual ajusta el porcentaje acumulado de precipitación en Y contribuida por el porcentaje acumulado de días X llevado a cabo en un lugar, en el periodo 1964-2004, con el cual es posible generar superficies de concentración pluviométrica. Donde las máximas concentraciones registradas en el valle del rio Mantaro, posiblemente estén asociadas a la dinámica de los vientos, como la corriente de chorro de Sudamérica, que se adentran al valle proveniente del Norte y Sur. Donde el 25% de días más lluviosos representan el 60% o más de la cantidad total de días con lluvia.

Spatial variability of concentration and aggressiveness of precipitation in North-East of Algeria

AbstractIn this study, the spatial variation of daily and monthly concentration precipitation index and its aggressiveness were used in 23 rainfall stations in the extreme north-east of Algeria over the period 1970–2010. The trend was analysed by the Mann–Kendall (MK) test. The results show that daily precipitation concentration index (CI) values are noticeably higher in places where the amount of total precipitation is low, the results of MK test show that areas of high precipitation concentration tend to increase. The seasonality and aggressiveness of precipitation are high in the eastern and western parts of the study region (eastern and central coastal of Constantine catchments), whereas a moderately seasonal distribution with low aggressiveness is found in the middle of the study area (plains and central Seybouse catchment). As a result, the modified Fournier index (MFI) has a significant correlation with annual precipitation, whereas theCIand monthly precipitation concentration index (PCI) show an opposite correlation in relation to annual precipitation.

Spatio‐temporal variability of daily precipitation concentration in Spain based on a high‐resolution gridded data set

ABSTRACTAn analysis of the spatial and temporal variability of daily precipitation concentration (CI) in Spain was made based on a high‐resolution (5 × 5 km) daily gridded precipitation data set for the 1950–2012 period. For each grid point in the Iberian Peninsula (IP) and Balearic and Canary Islands, the average annual CI was computed, as well as its coefficient of variation and the 5th and 95th percentiles. Annual values were also computed, and the time series of the index were used to assess temporal trends over the whole period. The spatial distribution of the CI showed a strong relationship with the orographic barriers near the coastlines. The Canary Islands showed the highest values of CI, along with the eastern Mediterranean facade of the IP. The highest inter‐annual variations of the CI occurred in the southern IP and in the southern Canary Islands. The trends of CI were, overall, positive and significant, which indicates an increase of daily precipitation concentration over the study period and an increasing environmental risks scenario where erosivity, torrentiality, and floods may become more frequent.

Spatial distribution of the daily precipitation concentration index in Southern Russia

The territory of Southern Russia presents a great diversity of climates and complex orography that lead to a very different precipitation distribution. Annual precipitation amounts differ between 222mm in the coast of the Caspian Sea and >2000mm in the highest parts of the Caucasus Mountains. In order to investigate the statistical structure of daily precipitation across the study region the daily precipitation Concentration Index (CI) was used. In present paper, the CI was calculated for 42 meteorological stations during the 1970–2010 period. The analysis of precipitation concentration identified that the distribution of daily precipitation is more regular over the west, north and south regions compared to the east (the Caspian Sea coast and the Caspian Depression). The Crimean peninsula is characterized by low CI values in the north and high values in the eastern part.

Spatial and temporal distribution of rainfall and drought characteristics across the Pearl River basin

Understanding rainfall trends as well as drought characteristics plays a key role in watershed development and management. In this study, the spatial and temporal characteristics of rainfall and drought based on temperature and precipitation data observed in 48 meteorological stations from 1959 to 2012 across the Pearl River Basin in China were analyzed. The possible influence of El Nino-Southern Oscillation (ENSO) and El Nino Modoki (ENSO_M) events on seasonal drought based on the Standardized Precipitation-evapotranspiration Index (SPEI) were also investigated. The results show that annual and seasonal rainfall decreased slightly in most areas, annual and seasonal daily precipitation concentration decreased in a few areas, monthly rainfall had an irregular distribution but with no significant trend detected, and rainfall seasonality increased in most areas. Drought tended to worsen during recent years, especially in the upper reaches, and seasonal drought also tended to become serious or occurred frequently across the Pearl River Basin. The drought patterns are not only related to the decreasing trends in rainfall but also to changes in the daily rainfall concentration, monthly rainfall heterogeneity, and rainfall seasonality. Both ENSO and ENSO_M events had an influence on summer drought in the middle-upper reaches. The ENSO events dominated the patterns of autumn drought in the Pearl River Delta, and the ENSO_M events strongly affected the changing patterns of autumn drought in the middle-upper reaches and northern parts of the middle-lower reaches.

Precipitation trends and a daily precipitation concentration index for the mid-Eastern Atlantic (Canary Islands, Spain)

This paper pursues two objectives: first, to determine the trends of seasonal and annual precipitation in the Canary Islands and, second, to identify trends in the daily precipitation concentration index (CI). For the first objective, we used data from 1970-2013 of 23 rainfall stations located on different islands, after verifying the homogeneity of their series. For the second, the sample was reduced to eleven series since deficiencies in data records of less than 1 mm of daily precipitation were appreciated. We used the nonparametric Mann-Kendall test to determine whether the series showed linear trends in annual and seasonal precipitation and in the values of CI. The seasonal results showed negative trends in spring and winter in almost all the time series considered, especially in the north of Gran Canaria and Tenerife. Conversely, 78% of the series in autumn recorded an increase in the precipitation. The annual balance indicated a decline of rainfall in most of the locations, because of the high concentration of precipitation in winter. Finally, the majority of the time series exhibited a trend toward a greater concentration of daily rainfall, in particular those series located in areas where the main towns are settled, which is an important issue to consider because of severe flooding and other geomorphological processes.

Erratum to: Spatial analysis and temporal trends of daily precipitation concentration in the Mantaro River basin: central Andes of Peru

Erratum to: Spatial analysis and temporal trends of daily precipitation concentration in the Mantaro River basin: central Andes of Peru

Spatial analysis and temporal trends of daily precipitation concentration in the Mantaro River basin: central Andes of Peru

The analysis of annual or seasonal data can lead to misinterpretation of spatio-temporal rainfall distribution. A high percentage of total annual precipitation can fall in just a few days, causing floods or landslides. Large economic losses from these events are particularly common in Peru, where the daily precipitation has been poorly investigated. This study presents a spatio-temporal analysis of concentration index over the Mantaro River basin in the central Peruvian Andes. Daily rainfall data recorded at 46 rainfall stations between 1974 and 2004 were selected in this study. In terms of average values, the analysis of daily rainfall indicates that low-intensity events account for 38 % of rainy days but only approximately 9 % of the total rain amount. In contrast, high- and very high-intensity events account for 35 % of rainy days and approximately 71 % of the total rain amount. The results also indicate higher concentration and lower intensity over the Northern and Central regions, compared to Southern region of the basin. Rainfall concentration gives evidence of why some of these places are more likely to be affected by extreme weather events; spatial distribution of event intensity can be partly explained by daily rainfall heterogeneity and orography. Moreover, Mann–Kendall test mostly shows a significant change toward a weaker seasonality of daily precipitation distribution over high-mountain regions.

Daily precipitation concentration around the world according to several indices

The temporal concentration of precipitation may be characterized using several methods. For climate-scale precipitation, concentration measures are usually performed by means of dimensionless indices such as the Gini index (GI) or the Theil index. For the purposes of the present paper, a set of 66 409 daily time series from around the world were analysed to estimate the climatic concentration of precipitation. To this end, some of the most widely used indices were tested, i.e. the Theil index, the Gini index, the concentration index, the classic n index and an ordered version of the n index. Results show a strong connection between several indices, mainly between the GI and the ordered n index. The high correlation of these indices (R = 0.98) reflects a theoretical connection between the shape and integration of the Lorenz curve. With regard to spatial distribution, the three main indices present the same relative areas of high and low concentration. The high temporal concentration of precipitation is generally linked to the rapid pace of physical processes such as convection in areas with a high degree of insolation and warm seas. The low temporal concentration of rainfall can be interpreted as a consequence of regular patterns (maritime flows or highly recurrent storms). A relationship between the number of rainy days and concentration indices was noted; however, their correlation depends on the region analysed.

Spatiotemporal variability of precipitation concentration in western Turkey

This paper addressed the spatial and temporal variations of precipitation concentration across western Turkey, by analyzing daily and monthly precipitation time series recorded at 28 stations over the period 1966–2011. Four indices: daily precipitation concentration index (DPCI), monthly precipitation concentration index (MPCI), precipitation concentration degree (PCD) and precipitation concentration period (PCP) were used. The results showed higher values of DPCI in northwestern and southern parts and lower values in western-central, central, eastern and northeastern parts, and the southern part was the most critical part of the study area, with the highest values of DPCI, MPCI, PCD and annual total precipitation, but the lowest number of rainy days. MPCI and PCD values showed a seasonal precipitation regime over the whole study area and exhibited a pattern decreasing from southwest to northeast, which implies a more uniform distribution of monthly rainfall in a year toward the northeast. PCP values showed that annual precipitation mainly falls in December and January. Trend analysis demonstrated mostly non-significant decreasing trends for all indices, implying a very slight tendency toward a more regular precipitation distribution in a year and a slightly earlier occurrence of precipitation over western Turkey.

Spatial distribution of the daily precipitation concentration index in Algeria

Abstract. In this paper, the spatial and temporal distribution of the daily precipitation concentration index (CI) in Algeria (south Mediterranean Sea) has been assessed. CI is an index related to the rainfall intensity and erosive capacity; therefore, this index is of great interest for studies on torrential rainfall and floods. Forty-two daily rainfall series based on high-quality and fairly regular rainfall records for the period from 1970 to 2008 were used. The daily precipitation CI results allowed the identification of three climate zones: the northern country, characterized by coastal regions with CI values between 0.59 and 0.63; the highlands, with values between 0.57 and 0.62, except for the region of Biskra (CI = 0.70); and the southern region of the country, with high rainfall concentrations with values between 0.62 and 0.69.

La concentración pluviométrica diaria y las secuencias lluviosas en Canarias: factores de peligrosidad

Texto resumen.

Trending Regional Precipitation Distribution and Intensity: Use of Climatic Indices

Trends and variability of annual precipitation total, annual number of rainy days and two climate change related precipitation indices named Simple Daily Intensity Index (SDII) and Precipitation Concentration Index (PCI) have been investigated in this study. The analysis was based on daily and monthly precipitation data of 35 observatory stations all over Bangladesh for the study period of 1971-2010. Mann Kendall test was performed to detect the trend and Sen’s slope method to determine the magnitude of change. The results indicate statistically significant (95% confidence level) negative trend in 4 stations and significant positive trend in 2 stations for annual precipitation total. Significant positive trend in 9 stations for annual number of rainy days, significant negative trend in 6 stations for SDII and for PCI, and significant negative trend in 6 stations were found all over Bangladesh in this study. The values of PCI indicate strongly irregular precipitation distribution in South Eastern Region (SER) and mostly irregular distribution in other regions. On the other hand values of SDII indicate strong precipitation intensity in SER and mostly moderate intensity in other regions all over the country.

Analysis of daily rainfall concentration in New Zealand

A higher precipitation concentration, represented by greater percentages of the yearly total precipitation in a few very rainy days, has the potential to impact considerably on water resources. In this paper, an investigation of the spatial and temporal patterns of daily precipitation concentration in New Zealand has been carried out by means of a daily precipitation dataset. Results show a different behavior between North Island, with the most critical rainfall concentration, and South Island, where precipitation concentration values on the eastern side are comparable to those of North Island, while the western side presents the lowest values of precipitation concentration. On a seasonal scale, the spatial gradients for summer and autumn are similar to the annual one. The application of the Mann–Kendall test shows a general negative trend detected in the eastern part of North Island, in particular in winter and autumn, and a west/east difference trend in South Island, in particular in winter and summer.

Spatial and temporal variability of daily precipitation concentration in the Lancang River basin, China

• A Lorenz curve is an effective way of assessing rainfall distribution. • Two indexes of Gini coefficient and Lorenz asymmetry coefficient from Lorenz Curve were defined. • A study of the rainfall concentration in the Lancang River has been carried out. • Significant trends were found in precipitation concentration index. • This work sheds new light on changing properties of rainfall in both time and space. The Lorenz Curve, a concept used in economic theory, is used to quantify spatial–temporal variability in the daily time series of precipitation concentrations. The Lorenz Curve provides a graphical view of the cumulative percentage of total yearly precipitation. In addition, further extraction of the data using the Gini coefficient and Lorenz asymmetry coefficient provides a two-parameter measure of precipitation concentration and an explanation of the basis for the underlying inequalities in precipitation distribution. Based on the calculation of the precipitation concentration index (CI) and the Lorenz asymmetry coefficient ( S ) values from 1960 to 2010, variations in the trends and periodic temporal–spatial patterns of precipitation at 31 stations across the Lancang River basin are discussed. The results are as follows: (1) highest precipitation CI values occurred in the southern Lancang River basin, whereas the lowest precipitation CI values were mainly observed in the upper reaches of the Lancang River basin, which features a more homogeneous temporal distribution of rainfall. S values throughout the entire basin were less than one, indicating that minor precipitation events have the highest contribution to overall precipitation inequality. (2) Application of the Mann–Kendall test revealed that a significant, decreasing trend in precipitation CI that exceeding the 95th percentile was detected in the upper and middle reaches of the Lancang River basin. However, there was only one significant (0.05) S value trend throughout the river. (3) Climate jumps in annual CI occurred during the early 1960s, 1970s and 1980s at Jinghong, Deqin and Zaduo stations, respectively. (4) Dominant periodic variations in precipitation CI, with periods of 4–17 years, were found. These results allow for an improved understanding of extreme climate events and improved river basin water resource management.