simple daily intensity index
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Climate ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 160
Author(s):  
Ezéchiel Obada ◽  
Eric Adechina Alamou ◽  
Eliezer Iboukoun Biao ◽  
Esdras B. Josué Zandagba

Observed rainfall data (1961–2016) were used to analyze variability, trends and changes of extreme precipitation indices over Benin. Nine indices out of the ones developed by the Expert Team on Climate Change Detection and Indices (ETCCDI) were used. The results indicate a mix of downward and upward trends for maximum 1-day precipitation (RX1day) and maximum 5-days precipitation (RX5day). Decrease trends are observed for annual total precipitation of wet days (P), while significant increases are found for the simple daily intensity index (SDII). The number of wet days (RR1) and maximum consecutive dry days (CDD) show a mix of increase/decrease trends. However, the number of heavy (R10) and very heavy (R20) wet days and maximum consecutive wet days (CWD) show decreased trends. All wet indices increased over 1991–2010 in relation to 1971–1990. The increase in all wet indices over Benin could explain the intensification of hydrology, and the increase in the frequency and the intensity of floods. It caused damages such as soil erosion, crop destruction, livestock destruction, displacement of populations, proliferation of waterborne diseases and loss of human life. Some adaptive strategies are suggested to mitigate the impacts of changes in extreme rainfall.


2020 ◽  
Vol 18 (1) ◽  
pp. 73-81
Author(s):  
Heri Mulyanti ◽  
Harjono Harjono ◽  
Mrabawani Insan Rendra

Hujan ekstrem erat kaitannya dengan bencana hidrometeorologi. Bengawan Solo Hilir merupakan wilayah yang rawan terhadap kejadian banjir maupun kekeringan. Penelitian bertujuan untuk: a) mengidentifikasi perubahan curah hujan ekstrem di Bengawan Solo Hilir tahun 1979-2017; b) menjelaskan kejadian hujan ekstrem saat kejadian ENSO (El Nino/ Southern Oscillation). Data curah hujan harian dari 10 stasiun digunakan untuk mendapatkan indeks eksrem berupa Rx1hari, Rx5hari, P95, P99, dan Simple Daily Intensity Index (SDII). Tren hujan monotonik dihitung menggunakan statistik Mann-Kendall, adapun besarnya perubahan dianalisis menggunakan uji Sen’s slope. Hubungan antara hujan ekstrem dengna kejadian ENSO diketahui berdasarkan nilai korelasi Spearman-rank. Hasil penelitian menunjukkan bahwa sebagian besar stasiun hujan bagian selatan mengalami penurunan hujan ekstrem (tren negatif). Perubahan hujan musiman didominasi bulan Maret-April-Mei dengan kecenderungan negatif. Kejadian ENSO tidak langsung berakibat pada intensitas hujan ekstrem skala harian. Indeks ENSO lebih tepat digunakan untuk analisis indeks ekstrem dengan skala kumulatif antarmusim maupun antartahun.  


Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2616 ◽  
Author(s):  
David Dunkerley

Rainfall intensity extremes are relevant to many aspects of climatology, climate change, and landsurface processes. Intensity is described and analysed using a diversity of approaches, reflecting its importance in these diverse areas. The characteristics of short-interval intensity extremes, such as the maximum 5-min intensity, are explored here. It is shown that such indices may have marked diurnal cycles, as well as seasonal variability. Some indices of intensity, such as the SDII (simple daily intensity index), provide too little information for application to landsurface processes. Upper percentiles of the intensity distribution, such as the 95th and 99th percentiles (Q95 and Q99) are used as indices of extreme intensity, but problematically are affected by changes in intensity below the nominated threshold, as well as above it, making the detection of secular change, and application to sites with contrasting rainfall character, challenging. For application to landsurface processes, a new index is introduced. This index (RQ95), is that intensity or rainfall rate above which 5% of the total rainfall is delivered. This index better reflects intense rainfall than does Q95 of even 5-min accumulation duration (AD) rainfall depths. Such an index is helpful for detecting secular change at an observing station, but, like Q95, remains susceptible to the effects of change elsewhere in the distribution of intensities. For understanding impacts of climate and climate change on landsurface processes, it is argued that more inclusive indices of intensity are required, including fixed intensity criteria.


Geografie ◽  
2019 ◽  
Vol 124 (3) ◽  
pp. 237-264 ◽  
Author(s):  
Iwona Pińskwar ◽  
Adam Choryński ◽  
Dariusz Graczyk ◽  
Zbigniew W. Kundzewicz

This paper examines observed changes in the indices of mean precipitation in Poland, based on daily precipitation records for 45 stations in Poland from 1961 to 2017. Changes in annual, semi-annual, seasonal, as well as monthly precipitation totals are examined. In addition, changes in the number of days with precipitation (≥ 1 mm), as well as in the Simple Daily Intensity Index and the ratio of precipitation in the warm half-year to precipitation in the cold half-year are studied. Many changes are detected, but most of them are not statistically significant at the 0.1 level. Yet, there are regionally consistent seasonal changes, with a dominating clear precipitation increase in spring and winter. The Student’s t-test for the comparison of means for two intervals: 1961–1990 and 1991–2017 revealed statistically significant increases for annual and spring precipitation, as well as for Simple Daily Intensity Index, and monthly data: increases for February, March, July, September, October and decreases for: June, August, November, December.


2013 ◽  
Vol 6 (4) ◽  
pp. 713 ◽  
Author(s):  
Priscila V. dos Santos ◽  
Rosaline Dos Santos ◽  
Maytê D. L. Coutinho

O objetivo do presente trabalho é estimar e analisar índices de detecção e monitoramento de mudanças climáticas, decorrentes da precipitação diária, para o Estado de Pernambuco, verificar sua possível dependência das anomalias de temperatura da superfície do mar e examinar suas influências sobre a dinâmica da vegetação, medida pelo Índice de Vegetação por Diferenças Normalizadas (IVDN), e variabilidade do clima, estimada pelo Índice Inverso de Aridez de Budyko (IIAB) anual. Para isso utilizou-se dados de precipitação totais diários de 26 localidades, anomalias de TSM para o período de 1964 a 2006, IVDN mensais de 1982 a 2001 e estimativa de temperaturas do ar média, máxima e mínima. Observou-se um decaimento da precipitação total anual, da intensidade simples diária da precipitação, dos dias consecutivos úmidos, dos dias com chuva superior a 20mm/dia e inferior a 50mm/dia, e aumento dos dias consecutivos secos. Verificou-se que, além do total anual de precipitação, o número de dias consecutivos secos, número de dias no ano com chuvas acima de 10mm/dia e intensidade simples diária de precipitação são dependentes dos padrões de anomalias de TSM nos Oceanos Pacífico Equatorial e Atlântico Tropical. O IVDN é influenciado pela precipitação total e pelo número de dias com chuvas superiores a 10mm/dia, principalmente no Alto Sertão do Estado. O índice inverso de aridez de Budyko é dependente das configurações das anomalias de TSM dos Oceanos Pacífico Equatorial e Atlântico Tropical Norte, e exerce influência sobre o IVDN. A B S T R A C T The objectives of the present work are: to compute and to analyze climate extreme indexes for monitoring and detecting climate change, for the state of Pernambuco; to verify the possible dependence of the extreme indexes of the anomalies of the sea surface temperature and to examine the influences of the extreme indexes on the dynamics of the vegetation, measured by NDVI (Normalized Difference Vegetation Index), and climate variability, evaluated for IIAB (Aridity Inverse Index of Budyko) annual. It was used precipitation diaries data from 26 meteorological stations, anomalies of SST for the period from 1964 to 2006, monthly NDVI from 1982 to 2001 and the mean, maxima and minima air temperature. It was observed a decline of the annual total precipitation, precipitation simple daily intensity index, consecutive wet days and days with superior rains to 20mm/day and inferior to 50mm/day. And it was verified an increase of the consecutive dry days. It was verified that the annual total of precipitation, number of consecutive dry days, number of days in the year with rains above 10mm/day and precipitation simple daily intensity index are dependent of the SST anomalies patterns on the Equatorial Pacific and Tropical Atlantic Oceans. NDVI is influenced by the total precipitation and for the number of days with superior rains to 10mm/day, mainly on the Sertão of the State. Aridity inverse index of Budyko is dependent of the SST anomalies configurations on the Equatorial Pacific and Northern Tropical Atlantic Oceans, and it exercises influence on NDVI. Keywords: climate, climatic changes, semiarid, coast.


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