Spatio-temporal evolution characteristics of precipitation in the north and south of Qin-ba Mountain area in recent 43 years

Abstract Using the daily precipitation data at 89 stations during 1975–2017 in the Qin-ba Mountain area, variation characteristics of different-grade precipitation in the north and south of the Qin-ba Mountain area are analyzed by the linear regression, Mann-Kendall test, and correlation analysis, based on the precipitation grade classification standard proposed by Dai Aiguo and the division of the geo-ecological boundary in mountain range presented by Kang Muyi. The results are as follows: (1) Light rain occurs most frequently, and the percentage of light rain in the north is twice that of the southern region. Rainstorms are the most rare. Precipitation above 800 mm mainly occurs south of the study area, and the result is consistent with the boundary between the north and south of the precipitation. (2) The beginning of precipitation mainly occurs in early April. The high precipitation concentration (PCD) in the north is an important reason for the debris flow disaster. The north-south precipitation concentration period (PCP) is about 1 month ahead of the central part. (3) In the past 43 years, the overall precipitation in the Qin-ba Mountain area has shown a decreasing trend, with the frequency of light rain and the percentage of heavy rain decreasing year by year. (4) The frequency of light rain is negatively correlated with other frequencies. In addition, the fewer days of precipitation, the later the precipitation concentration period (PCP) occurs, which means that the disaster occurs later.

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Temporal and Spatial Variations of Precipitation Change from Southeast to Northwest China during the Period 1961–2017

Water ◽

10.3390/w12092622 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2622

Author(s):

Zhu Li ◽

Honghu Liu

Keyword(s):

Daily Precipitation ◽

Global Climate ◽

Heavy Rain ◽

Northwest China ◽

Annual Rainfall ◽

Trend Test ◽

Spatiotemporal Variations ◽

Light Rain ◽

Daily Precipitation Data ◽

Northwest Region

Global climate change is significant, and the spatiotemporal variations of precipitation associated with it are pronounced. Based on the daily precipitation data from 10 weather stations located from southeast to northwest across China from 1961–2017, the Mann–Kendall trend test was generally applied to analyze the spatiotemporal variations of precipitation. The factors influencing the precipitation changes were investigated. The results revealed that (1) the annual, summer, and winter rainfall amount (RA) exhibited increasing rates of 16.36, 12.31, and 2.49 mm/10 year, respectively. The change rates of annual rainfall days (RD) were 2.68 day/10 year in the northwest region and −1.88 day/10 year in the southeast. The annual and seasonal daily precipitation on rainy days (RP) exhibited an increasing trend. (2) All of the RA, RD, and RP values initially increased, then decreased, and then slightly increased from Southeast to Northwest China. These results proved that the RA increased with the increase of light rain in Northwest China and heavy rain in Southeast China. In addition, changes in the monsoon have altered the rate at which RA, RD, and RP vary with distance from the sea. These findings may help to provide suggestions for the rational spatial utilization of water resources in China.

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DISTRIBUCIÓN ESPACIAL DEL ÍNDICE DE CONCENTRACIÓN DE PRECIPITACIÓN DIARIA EN LOS ANDES CENTRALES PERUANOS: VALLE DEL RIO MANTARO

Revista TECNIA ◽

10.21754/tecnia.v19i2.113 ◽

2017 ◽

Vol 19 (2) ◽

pp. 13 ◽

Cited By ~ 3

Author(s):

Ricardo Zubieta ◽

Miguel Saavedra

Keyword(s):

Concentration Index ◽

Daily Precipitation ◽

River Valley ◽

Spatial And Temporal Patterns ◽

Precipitation Concentration ◽

The North ◽

Palabras Clave ◽

Del Rio ◽

North And South ◽

Rainy Days

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. Palabras clave.-Índice de concentración, Precipitación diaria; Valle del rio Mantaro. ABSTRACTHigh percentages total precipitation concentration in a few very rainy days can increase the potential of erosion, instability and risks of floods, these problems are common in Peru. So it is important to know about the daily precipitation. This paper presents, an investigation of the spatial and temporal patterns of daily precipitation concentration, in central Andes of Perú, the Concentration index (CI) was evaluates measurement the varying weight of daily precipitation, the contribution of the days of greatest rainfall to the total amount. The index is applied to exponential curves such as Y = aX exp(bX), which adjust the accumulated percentages of precipitation Y contributed by the accumulated percentage of days X on which it took place, in the period 1964-2004, with which it is possible to generate concentration surfaces daily pluviometric. The highest concentrations recorded in the Mantaro river valley, may be associated with the dynamics of the winds as the stream in South America, leading into the valley from the north and south, where 25% of rainy days account for 60% or more of the total number of days with rain. Keywords.- Concentration index; Daily precipitation; Mantaro river valley.

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Spatiotemporal Changes in Precipitation Concentration Indicators Over Iran

10.21203/rs.3.rs-1055082/v1 ◽

2021 ◽

Author(s):

Mohammad Darand ◽

Farshad Pazhoh

Keyword(s):

Change Point ◽

Spatiotemporal Variability ◽

Precipitation Concentration Index ◽

South Eastern ◽

Precipitation Concentration ◽

Oman Sea ◽

The North ◽

Daily Precipitation Data ◽

Concentration Degree ◽

Period Of Occurrence

Abstract This study was conducted to investigate the spatiotemporal variability in precipitation concentration over Iran. For that purpose, daily precipitation data with a spatial resolution of 0.25° × 0.25° from the Asfazari database for the period from 01/01/1962 to 31/12/2019 were used. Three indices including the precipitation concentration index (PCI), precipitation concentration period (PCP), and precipitation concentration degree (PCD) were utilized for examination of the variability in precipitation concentration over the country. The results demonstrated that the central, south-eastern, and eastern parts of the country exhibited maximum temporal precipitation concentration, while the least precipitation concentration could be observed over the Caspian coasts and the northern half of the country. The year 1998 was selected as the change point due to the considerable difference in the values of the examined indices, and the long-term statistical period was divided into two sub-periods before and after the change. During the sub-period after the change point (1999-2019), precipitation concentration has increased in the western, central, eastern, and south-eastern parts of Iran, according to PCI and PCD, and has decreased in the North and Northeast and along the northern coastline of Oman Sea. Furthermore, there have been great spatial differences in the period of occurrence of precipitation along the Northern coasts, according to PCP, varying from November, along the Caspian coasts, to August, along the northern foothills of Alborz Mountains. The PCP index has increased during the sub-period after the change point along the northern coastlines of Persian Gulf and Oman Sea and in parts of the North (along Alborz Mountains), indicating a shift in the period of precipitation from winter to the warm seasons of spring and summer. Moreover, the decrease in PCP in the Northwest and Northeast suggested that the period of occurrence of precipitation has shifted from the second half of winter toward early winter and late fall. After the year of change point, the frequency of rainy days and precipitation have decreased, and PCI and PCD have increased.

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The Secondary Low and Heavy Rainfall Associated with Typhoon Mindulle (2004)

Monthly Weather Review ◽

10.1175/2007mwr2069.1 ◽

2008 ◽

Vol 136 (4) ◽

pp. 1260-1283 ◽

Cited By ~ 27

Author(s):

Cheng-Shang Lee ◽

Yi-Chin Liu ◽

Fang-Ching Chien

Keyword(s):

Heavy Rainfall ◽

Numerical Study ◽

North Coast ◽

Mountain Range ◽

Mountain Area ◽

The North ◽

Main Circulation ◽

Upper Level ◽

The Taiwan Strait ◽

Strong Vorticity

Abstract This paper presents an observational and numerical study of Typhoon Mindulle (2004) as it affected Taiwan. Mindulle made landfall on the east coast of Taiwan at 1500 UTC 1 July 2004, and after 13 h, it exited Taiwan from the north coast. Severe rainfall (with a maximum amount of 787 mm) occurred over central-southwestern Taiwan on 2 July 2004. During the landfall of Mindulle’s main circulation, a secondary low formed over the Taiwan Strait. However, the secondary low, after it developed significantly (vorticity exceeded 5 × 10−4 s−1 over a 30-km radius), did not replace the original center as was observed in many other storms. Instead, it moved inland and dissipated after the original center redeveloped near the north coast of Taiwan. In this study, the evolution of the secondary low, the redevelopment of the primary center, and the processes leading to the severe rainfall were examined. Results showed that the processes leading to the formation and the development of the secondary low were similar to those described in previous studies. These processes include the leeside subsidence warming, the horizontal transport of vorticity around the northern tip of the Central Mountain Range (CMR), and the overmountain upper-level vorticity remnant. However, because of the northward track, Mindulle preserved some strong vorticity on the eastern slope of the CMR. This strong vorticity remnant was steered northward over the ocean offshore from the north coast where the redevelopment of the primary center occurred. This “quasi-continuous track” of Mindulle has not been documented in previous studies. The vortex interaction between the redeveloped primary center and the secondary low resulted in the northeastward movement of the secondary low, which then dissipated after making landfall. Analyses also showed that even though heavy rainfall would occur over the mountain area when only the southwesterly flow prevailed, as on 3 July 2004, Typhoon Mindulle and the secondary low provided extra convergence that resulted in the west–east-oriented convective bands. These convective bands and the orographic lifting of the circulation associated with the secondary low resulted in the heavy rainfall over the central-western plains area.

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

Cuadernos de Investigación Geográfica ◽

10.18172/cig.3095 ◽

2017 ◽

Vol 43 (1) ◽

pp. 255 ◽

Cited By ~ 5

Author(s):

P. Máyer ◽

M.V. Marzol ◽

J.M. Parreño

Keyword(s):

Time Series ◽

Canary Islands ◽

Concentration Index ◽

Daily Precipitation ◽

Daily Rainfall ◽

Kendall Test ◽

High Concentration ◽

Precipitation Concentration Index ◽

Precipitation Concentration ◽

The North

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.

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