Expert Team On Climate Change Detection , Monitoring And Indices Research Articles

Analysis of The Occurrence of Extreme Events in The City of Rio de Janeiro/RJ

Objective: To investigate the trends of extreme rainfall and temperature indices in the city of Rio de Janeiro, as measures to assess climate change. Theoretical benchmark: Extreme climatic events have been observed more frequently than has become a concern all over the world, so the investigation of trends in extreme precipitation and temperature indices makes it necessary to enter how this dynamic in climatic conditions affects the city of Rio de Janeiro. Method: The methodology for assessing climate change will be used from the indicators defined by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI) panel, but of the 27 indicators proposed by the panel, 12 indicators were used that were more adapted to the reality of the city of Rio de Janeiro, for the simulation of climate data, data from the stations of the National Institute of Meteorology (INMET) and for the simulation of the indicators in the RClimdex software. Daily data of 53 years of 19 (six) stations obtained from the historical series of the period between 1970 and 2023 were analyzed, for the precipitation indices: PRCPTOT, R10, R20, R95p and R99p, and for the temperature indices: TX90p, TN90p, TMAXmean, TMINmean and DTR. Results and conclusion: The results indicate a trend of decreasing rainfall of low rainfall and a significant increase of extreme rainfall, the data also show a decrease of thermal amplitude, with the increase of minimum temperatures and a moderate decrease of maximum temperatures. Implications of the research: The study in question presents internationally validated indicators that demonstrate how extreme events are intensifying in the city of Rio de Janeiro. Originality/value: The data demonstrated in this research are of extreme importance as a source of research for future works that address this theme, besides serving as a subsidy to decision makers to propose adaptive measures to the territory, in the face of the intensification of extreme events in the city of Rio de Janeiro.

TEMPORAL TRENDS OF CLIMATE INDICES ASSOCIATED WITH PRECIPITATION AND AIR TEMPERATURE IN MINAS GERAIS, BRAZIL

The objective of this study was to evaluate the trends of four climatic extremes indices related to minimum and maximum air temperatures and three related to precipitation in Minas Gerais state, Brazil, from 1961 to 2010. These indices were developed by the Expert Team on Climate Change Detection Monitoring and Indices (ETCCDMI) with the aim of subsidizing climate change on global, regional and local levels. Daily rainfall and temperature long-term series were obtained from the National Institute of Meteorology (INMET) for 47 municipalities, in different regions of the state. The analyzes were conducted considering the four seasons of the year based on the Mann-Kendall and linear regression tests. There was a significant trend towards change in the indices related to minimum (TNn; TNx) and maximum (TXn; TXx) temperatures all over the state. Precipitation indexes (R10mm, R20mm and SDII) have showed no significant changes. The increase in the TNn, TNx, TXn and TXx has been observed in all seasons, except for autumn, and the TNx index in the winter. Both minimum and maximum temperatures indices have showed increase in greatest part of Minas Gerais in the spring, evidencing an expressive heating in this season and a premature summer onset. In the autumn, there was a downward trend in all temperature indices, characterizing an anticipation of winter. In winter, there was an upward trend in the TNn index and downward of the TNx in almost the entire state, indicating a reduction in the frost occurrence possibility, especially in the South and Southeast regions. The highest rates were observed in the Mid-west and Northwest regions. For the TXx index, in the summer there were upward trends throughout the state, especially in the North. Thus, important consequences to the agriculture planning and zoning have taken place as well as a proliferation of arbovirus diseases, affecting the life quality of the population.

Spatial and Temporal Trends in Diurnal Temperature and Precipitation Extremes in North Central Nigeria

Global warming and changes in precipitation patterns are among the major effects of climate change. In this study, the long-term variability in ambient surface temperature and precipitation were evaluated in the north central region of Nigeria (Abuja, Kogi, Kwara, Niger, and Plateau) using meteorological observations obtained from 1975 to 2008. Daily precipitation data from synoptic weather stations were carefully quality-controlled using the RClimdex 1.1 developed by Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI). The quality-controlled dataset were homogenized using RHtestsV4 and the detected change points were adjusted. Results showed a decrease in cool nights and cool days (TN10P, TX10P), and increasing trend in warm nights and days (TN90P, TX90P). The trend in rainfall is variable compared to changes in temperature. The precipitation indices indicated increasing trend in total annual precipitation (PRCPTOT), and a significant decrease in the number of consecutive wet days (CWD) in this region. In general, regional changes in climate temperature and precipitation extremes were significant (p < 0.05) and could result in serious climate induced effects.

Detection of trends for extreme events of precipitation in the Metropolitan Region of Belo Horizonte through statistical methods

ABSTRACT Extreme weather events have emerged as one of the main manifestations of climate change, being that the mitigation of the elapsed impacts demand studies of the magnitude and frequency of their occurrence. This study aims to identify the trends of extreme precipitation events in the Metropolitan Region of Belo Horizonte, especially concerning their frequency. The trends of precipitation were studied with especial regard to the indices set by ETCCDMI (Expert Team on Climate Change Detection Monitoring and Indices), including time series of annual number of rainy days above a certain threshold recorded at fourteen rainfall gauging stations. One stage of this study consisted in surveying the flood occurrence in the area, besides analyzing the precipitation data corresponding to date of flood occurrences, in order to establish a threshold value beyond which an event would entail potential impacts. No regional index pattern could be set based on such results, although the rainfall station located in the city of Belo Horizonte reported a statistically significant increase in daily precipitation events above 10, 20, 30 and 40 mm, in maximum precipitation recorded over five consecutive days, in daily intensity, and in total annual precipitation. Abrupt changes in rainfall series were also recorded. The results have indicated that the city may be potentially impacted by extreme rainfall increase, probably associated to changes in temperatures on regional and local scales.

Rising Precipitation Extremes across Nepal

As a mountainous country, Nepal is most susceptible to precipitation extremes and related hazards, including severe floods, landslides and droughts that cause huge losses of life and property, impact the Himalayan environment, and hinder the socioeconomic development of the country. Given that the countrywide assessment of such extremes is still lacking, we present a comprehensive picture of prevailing precipitation extremes observed across Nepal. First, we present the spatial distribution of daily extreme precipitation indices as defined by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI) from 210 stations over the period of 1981–2010. Then, we analyze the temporal changes in the computed extremes from 76 stations, featuring long-term continuous records for the period of 1970–2012, by applying a non-parametric Mann−Kendall test to identify the existence of a trend and Sen’s slope method to calculate the true magnitude of this trend. Further, the local trends in precipitation extremes have been tested for their field significance over the distinct physio-geographical regions of Nepal, such as the lowlands, middle mountains and hills and high mountains in the west (WL, WM and WH, respectively), and likewise, in central (CL, CM and CH) and eastern (EL, EM and EH) Nepal. Our results suggest that the spatial patterns of high-intensity precipitation extremes are quite different to that of annual or monsoonal precipitation. Lowlands (Terai and Siwaliks) that feature relatively low precipitation and less wet days (rainy days) are exposed to high-intensity precipitation extremes. Our trend analysis suggests that the pre-monsoonal precipitation is significantly increasing over the lowlands and CH, while monsoonal precipitation is increasing in WM and CH and decreasing in CM, CL and EL. On the other hand, post-monsoonal precipitation is significantly decreasing across all of Nepal while winter precipitation is decreasing only over the WM region. Both high-intensity precipitation extremes and annual precipitation trends feature east−west contrast, suggesting significant increase over the WM and CH region but decrease over the EM and CM regions. Further, a significant positive trend in the number of consecutive dry days but significant negative trend in the number of wet (rainy) days are observed over the whole of Nepal, implying the prolongation of the dry spell across the country. Overall, the intensification of different precipitation indices over distinct parts of the country indicates region-specific risks of floods, landslides and droughts. The presented findings, in combination with population and environmental pressures, can support in devising the adequate region-specific adaptation strategies for different sectors and in improving the livelihood of the rural communities in Nepal.

Occurrence of extreme temperature events – A Probable risk on natural rubber cultivation

&lt;span style="line-height: 107%; font-family: 'Times New Roman','serif'; font-size: 12pt; mso-bidi-language: HI; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-ansi-language: EN-GB; mso-fareast-language: EN-US;" lang="EN-GB"&gt;Climate change and occurrence of extreme temperature events were studied in Kottayam, a major rubber growing district in Kerala. Occurrence of extreme temperature events can affect the livelihood of rubber growers apart from the ecological impact. The present study was conducted by analysing the occurrence of extreme temperature events in the past 40 years (1970-2010) using the RClimDex package developed by the Expert Team on Climate Change Detection Monitoring and Indices (ETCCDMI), Canada. Temporal variations in trends of occurrence of extreme temperature events were tested with Mann-Kendall trend analysis. The 5-year diurnal temperature range (DTR, difference between monthly mean maximum and minimum temperatures) increased from 7.8 (during 1970-1974) to 9.2 0C (during 2006-2010). The monthly mean maximum temperature increased by 0.035 0C per year. Frequency of occurrence of hot days increased at a rate of 0.56 per cent per year and the highest temperature recorded in a month showed an increase of 0.038 0C per year. As observed, the increasing trends in the occurrence of extreme temperature events may eventually lead to the warming up of the region in future. The study indicates that the projected warming tendency in the traditional rubber growing regions of India may affect the rubber cultivation adversely.&lt;/span&gt;

Variabilidade temporal e espacial da precipitação pluviométrica em Pernambuco através de índices de extremos climáticos

O presente artigo tem como objetivo analisar a tendência espacial e temporal da precipitação pluviométrica do Estado de Pernambuco, tendo como base índices de extremos climáticos e a técnica dos quantis. Os dados de precipitação pluviométrica diária foram oriundos do Climate Prediction Center (CPC) relativos ao período de 1978 a 2010. Para analisar a tendência da precipitação foram escolhidos os índices climáticos sugeridos peloExpert Team on Climate Change Detection Monitoring and Indices (ETCCDMI). Através do método de krigagem foi possível analisar a variabilidade espacial dos índices analisados. Os resultados demonstram predominância de tendência de aumento nos padrões pluviométricos em grande parte do Estado, com exceção do setor central da Região Metropolitana leste e parte central da Zona da Mata. Os resultados dos índices conjuntamente indicam que as chuvas estão cada vez mais concentradas em poucos dias ao longo do ano nos sertões e agreste de Pernambuco. Também sobre o sertão, foram encontrados os maiores números de episódios extremamente secos, assim como, a maior quantidade de ocorrência de eventos extremamente chuvosos, concentrados nos meses dezembro, janeiro e fevereiro, período chuvoso do Sertão de Pernambuco.

Study of Daily Extreme Temperature Indices over Sutlej Basin, N-W Himalayan Region, India

&lt;div&gt;&#x0D; &lt;p&gt;A detailed analysis of extreme temperature indices for the period of 1970-2005 is conducted over Sutlej river basin located in North-West Himalayan region. For this purpose, daily records of maximum and minimum temperature data were procured from Bhakara Beas Management Board, India for four stations. These stations are installed at varying height from 518m to 976m under different physiographic and climatic conditions. Fourteen extreme indices for temperature as specified by the World Meteorological Organization (WMO) Commission for Climatology (CCL)/Climate Variability and Predictability (CLIVAR) Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI) are derived with the aid of RClimDex software. &amp;nbsp;Linear Regression (LR) method is employed for detecting annual as well as monthly trends in extreme indices of temperature over the period of thirty six years (1970-2005). Large spatial and inter-annual variability in trends of extreme indices is observed. However, a rise in diurnal temperature range is observed for the basin as a whole. This may be attributed to the decrease observed in maximum T&lt;sub&gt;Min&lt;/sub&gt; (TXn) and warm nights (TN90p) coupled with the increase in maximum T&lt;sub&gt;Max&lt;/sub&gt; (TXx).&lt;/p&gt;&#x0D; &lt;/div&gt;&#x0D; &lt;p&gt;&amp;nbsp;&lt;/p&gt;&#x0D;

Analysis of temperature projections in the Koshi River Basin, Nepal

This study analyzes temperature projections in the Koshi River Basin in Nepal using data obtained from ten General Circulation Models (GCMs) for three IPCC Special Range of Emission Scenarios (SRES): B1, A1B and A2. Low resolution data of minimum and maximum temperature obtained from the selected GCMs was downscaled using the statistical downscaling model Long Ashton Research Station Weather Generator (LARS-WG) for ten stations located in two physiographic regions of the study area: the Middle Mountains (1500–2700 m) and the Siwalik Hills (700–1500 m). The projected temperature and differences in projections among individual GCM projections for changes in the mean value of seasonal and annual Tmin and Tmax are presented for three future periods: 2011–2030 (2020s), 2046–2065 (2055s) and 2080–2099 (2090s). We also analyzed the baseline period and future Tmin and Tmax data through seven indices, as recommended by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI). Results show that the LARS-WG model performs well when downscaling Tmin and Tmax. An increase in seasonal as well as mean annual minimum and maximum temperature is projected for all three future periods. Projected warming, as well as the differences among projections from different GCMs, increases with time for each of the three scenarios. The cold years during the 2055s and 2090s are expected to be hotter than the hot years during the baseline period. The increase in temperature, as well as the range of uncertainty, is expected to be higher in the Mountains than in the Hills. The number of summer days and tropical nights is expected to increase during all three future periods. The temperature of the coldest day, coldest night, warmest day and warmest night is also expected to increase in both the regions during all three future periods.

Recent Changes of Some Observed Climate Extreme Events in Kano

Observed rainfall and temperature data for the period 1960–2007 were used to examine recent changes of extreme climate over Kano, located in the Sahelian region of Nigeria. The RClimDex software package was employed to generate nine important climate indices as defined by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI). For the entire period, the results show a warming trend, an increased number of cool nights, more warm days, and a strong increase in the number of warm spells. The rainfall indices show a slight increase in annual total rainfall, a decrease in the maximum number of consecutive wet days, and a significant increase in the number of extremely wet days. Such changes in climate may result in an increasing demand for domestic energy for cooling and a higher evaporation rate from water bodies and irrigated crop. These findings may give some guidance to politicians and planners in how to best cope with these extreme weather and climate events.

Analysis of future precipitation in the Koshi river basin, Nepal

We analyzed precipitation projections for the Koshi river basin in Nepal using outputs from 10 General Circulation Models (GCMs) under three emission scenarios (B1, A1B and A2). The low resolution future precipitation data obtained from the GCMs was downscaled using the statistical downscaling model LARS-WG. The data was downscaled for 48 stations located in the six physiographic regions in the Koshi basin. The precipitation projections for three future periods, i.e. 2020s, 2055s and 2090s, are presented using empirical Probability Density Functions (PDFs) for each physiographic region. The differences between the mean values of individual GCM projections and the mean value of the multi-model for the three scenarios allow for the estimation of uncertainty in the projections. We also analyzed the precipitation of the baseline and future periods using six indices that are recommended by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI). Results indicate that not all GCMs agree on weather changes in precipitation will be positive or negative. A majority of the GCMs and the average values of all the GCMs for each scenario, indicate a positive change in summer, autumn and annual precipitation but a negative change in spring precipitation. Differences in the GCM projections exist for all the three future periods and the differences increase with time. The estimated uncertainty is higher for scenario A1B compared to B1 and A2. Differences among scenarios are small during the 2020s, which become significant during the 2055s and 2090s. The length of the wet spell is expected to increase, whereas the length of the dry spell is expected to decrease in all three future periods. There is a large scatter in the values of the indices: number of days with precipitation above 20 mm, 1-day maximum precipitation, 5-day maximum precipitation, and amount of precipitation on the days with precipitation above 95th percentile, both in direction and magnitude of the change.

The changing characteristics of monsoon rainfall in India during 1971-2005 and links with large scale circulation

This study examines the changes in monsoon rainfall of India using a suite of extreme indices defined by the Expert Team on Climate Change Detection Monitoring and Indices (ETCCDMI) to make the Indian results comparable internationally, in addition to the use of some relevant indices particularly developed for the Indian climate. To this end, the recently developed high resolution daily gridded (0.5° × 0.5°) rainfall dataset for the period 1971–2005 has been analysed using robust nonparametric techniques. Despite the high interannual variability and spatial diversity of the Indian climatology, the results reveal signal of changes for several extreme rainfall indices, generally consistent with the simulated outcome of an intensified Indian monsoon rainfall in the context of global warming. A predominant decrease in wet days, moderate and total rainfall is observed in the high rainfall regions of northeast, central and southwest India. In the active monsoon months of July and August, the dry spells defined by the maximum length of consecutive dry days (CDD) have increased significantly over the north and central regions of India, suggesting a serious threat to the Indian agriculture. Simultaneously, the extreme rainfall indices, based on the percentile and absolute values, show increasing trends over large parts of the country. The probability density function (PDF) of several indices show noticeable changes since the 1990s over the homogeneous central and northeast parts of India. The indices representing the total monsoon rainfall and dry spells are better correlated with the El Nino–Southern Oscillation (NINO3.4), compared to that of the Indian Ocean Dipole Mode Index (IODMI). The mapping of the observed rainfall trends and their correspondence to the large scale circulation modes is expected to assist the policy makers to prioritize the mitigation and adaptation strategies.

Changes in Twentieth-Century Extreme Temperature and Precipitation over the Western United States Based on Observations and Regional Climate Model Simulations*

Abstract Trends in extreme temperature and precipitation in two regional climate model simulations forced by two global climate models are compared with observed trends over the western United States. The observed temperature extremes show substantial and statistically significant trends across the western United States during the late twentieth century, with consistent results among individual stations. The two regional climate models simulate temporal trends that are consistent with the observed trends and reflect the anthropogenic warming signal. In contrast, no such clear trends or correspondence between the observations and simulations is found for extreme precipitation, likely resulting from the dominance of the natural variability over systematic climate change during the period. However, further analysis of the variability of precipitation extremes shows strong correspondence between the observed precipitation indices and increasing oceanic Niño index (ONI), with regionally coherent patterns found for the U.S. Northwest and Southwest. Both regional climate simulations reproduce the observed relationship with ONI, indicating that the models can represent the large-scale climatic links with extreme precipitation. The regional climate model simulations use the Weather Research and Forecasting (WRF) Model and Hadley Centre Regional Model (HadRM) forced by the ECHAM5 and the Hadley Centre Climate Model (HadCM) global models for the 1970–2007 time period. Comparisons are made to station observations from the Historical Climatology Network (HCN) locations over the western United States. This study focused on temperature and precipitation extreme indices recommended by the Expert Team on Climate Change Detection Monitoring and Indices (ETCCDMI).

Tendencias recientes e índices de cambio climático de la temperatura y la precipitación en Andorra, Pirineos (1935-2008)

This paper shows the results obtained for the calculation of annual and seasonal trends of maximum and minimum temperature and precipitation from three climatic series of the Principality of Andorra (Pyrenees), and located between 1140 and the 1645 m. The estimated trends have been obtained for the period 1935-2008 corresponding to the whole length of the series, and for the sub-period 1950-2008. From the same series, at a daily resolution, the indices of change defined by the ETCCDMI (Expert Team on Climate Change Detection Monitoring and Indices) have been also calculated. The results represent a solid description of the Andorran climate dynamics over the past eight decades and provide insight into the variability and climate change experienced in the Pyrenean country, characterized by its high altitude. The results confirm the trends identified regionally by other agencies, both French and Spanish. This confirms the significant increase in air temperature for the annual mean maximum temperature (0.13 to 0.15 oC/decade), for the summer maximum temperature (0.22 oC/decade), and the summer minimum temperature (0.11 oC/ decade). These trends are reinforced when the analysis focuses on the sub-period 1950-2008. For precipitation and for the period 1935-2008, only significant decreasing trends are obtained in the station Central and in summer (-5.4%/decade), while this behaviour is generalized and strengthened if we stick to the period 1950-2008. Finally, the results for the calculation of the ETCCDMI daily indices confirm and detail the results obtained at coarser resolution. Thus, the indices computed from the temperature series show an increase in extreme warm days and a decrease of their opposites. For precipitation rates, significant trends were not found for the period 1935-2008, while several indices did show statistically significant decreasing values for the sub-period 1950-2008.

Climatic changes in western North America, 1950–2005

AbstractThe rate of climatic change over western North America (WNA) is quantified for 485 climate stations for the period 1950–2005. Additionally, six stations with quality long‐term records were selected and analysed for the period 1906–2005. The indicators used were developed by the World Meteorological Organization (WMO) and the World Climate Research Program's Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI). From the 27 core indices, 4 temperature‐based and 4 precipitation‐based indicators were selected for in‐depth analysis. The 8 million km2 study area is comprised of the 22 contiguous US states and 4 Canadian provinces west of the Mississippi River and Great Lakes. The results were divided into six general regions for interpretation and presentation. GIS interpolation of station‐specific statistical output was completed to further aid in the identification of spatially coherent trends across WNA. Mean slopes were calculated over the whole study area, and by region, for each index, and then tested to determine if they were significantly different from zero.Results of the study show statistically significant historical climate trends across the study area. As expected in a region as geographically diverse as WNA, results differed between, and within, regions. Overall, temperature‐based indicators showed a general warming trend over the entire study area, with the greatest increases along the North American Cordillera. The trends in precipitation‐based indicators were more varied. General trends indicate moderately increasing precipitation volume and intensity over much of WNA. The strongest precipitation trends were found in areas with climate largely controlled by air masses originating over the Gulf of Mexico. Copyright © 2011 Royal Meteorological Society

Observed changes in extreme weather indices in Hong Kong

AbstractPast trends of the occurrences of extreme temperature and rainfall events in Hong Kong from 1885 to 2008 were examined using a suite of 27 extreme indices adopted from the core indices developed by the Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI) under the auspices of the World Meteorological Organization (WMO), with appropriate modification to suit the sub‐tropical climate of Hong Kong. Results showed that the extreme daily maximum and minimum temperatures, annual numbers of very hot days (daily maximum temperature ≥ 33.0 °C) and hot nights (daily minimum temperature ≥ 28.0 °C) as well as the warm spell duration index (WSDI) in Hong Kong exhibited statistically significant long‐term rising trends, whereas the annual number of cold days (daily minimum temperatures ≤ 12.0 °C) and cold spell duration (CSDI) index had a statistically significant decreasing trend. Regarding rainfall, the frequency of occurrence of extreme hourly, 2‐ and 3‐hourly rainfall amounts increased significantly. The fraction of annual total precipitation due to events exceeding the daily 95th percentile of the climatological normal (1971–2000) increased by 22 mm per decade in the same period, indicating that the contribution of heavy rain to the annual rainfall amount was increasing with time. However, the maximum length of dry spell in the summer months from April to September increased at a rate of 0.3 days per decade from 1885 to 2008. Using the time‐dependent generalized extreme value (GEV) distribution technique, the return period for the daily minimum temperature of 4 °C or lower had significantly lengthened from 6 years in 1900 to 163 years in 2000. The return period for an hourly rainfall of 100 mm or more had shortened from 37 years in 1900 to 18 years in 2000. Copyright © 2010 Royal Meteorological Society