Trends In Precipitation Extremes Research Articles

Changing features of extreme precipitation in the Yangtze River basin during 1961–2002

The total precipitation of the highest 1 day, 3 day, 5 day and 7 day precipitation amount (R1D, R3D, R5D and R7D) in the Yangtze River basin was analyzed with the help of linear trend analysis and continuous wavelet transform method. The research results indicated that: 1) Spatial distribution of R1D is similar in comparison with that of R3D, R5D and R7D. The Jialingjiang and Hanjiang river basins are dominated by decreasing trend, which is significant at >95% confidence level in Jialingjiang River basin and insignificant at >95% confidence level in Hanjiang River basin. The southern part of the Yangtze River basin and the western part of the upper Yangtze River basin are dominated by significant increasing trend of R1D extreme precipitation at >95% confidence level. 2) As for the R3D, R5D and R7D, the western part of the upper Yangtze River basin is dominated by significant increasing trend at >95% confidence level. The eastern part of the upper Yangtze River basin is dominated by decreasing trend, but is insignificant at >95% confidence level. The middle and lower Yangtze River basin is dominated by increasing trend, but insignificant at >95% confidence level. 3) The frequency and intensity of extreme precipitation events are intensified over time. Precipitation anomalies indicated that the southeastern part, southern part and southwestern part of the Yangtze River basin are dominated by positive extreme precipitation anomalies between 1993–2002 and 1961–1992. The research results of this text indicate that the occurrence probability of flash flood is higher in the western part of the upper Yangtze River basin and the middle and lower Yangtze River basin, esp. in the southwestern and southeastern parts of the Yangtze River basin.

Trends in extreme daily precipitation and temperature near lake Hövsgöl, Mongolia

AbstractA long‐term (1963–2002) set of daily maximum and minimum temperature and precipitation data are analyzed for the Hövsgöl Basin area, Mongolia. Six indices of extreme temperature and eight indices of extreme precipitation are examined. Results suggest that climate conditions over northern Mongolia are changing as indicated by a warming trend identified during the study period. Significant increases are detected in the annual number of hot days and warm nights in this region. Associated with these changes are concomitant decreases in the annual number of cold days and cold nights. The number of days with precipitation has increased slightly while the annual total precipitation has not significantly increased in northern Mongolia. On an average, there was no significant decrease in the maximum number of consecutive dry days or increase in the wet days. The 5‐day precipitation total showed a small increase. Copyright © 2006 Royal Meteorological Society.

Trends in Middle East climate extreme indices from 1950 to 2003

A climate change workshop for the Middle East brought together scientists and data for the region to produce the first area‐wide analysis of climate extremes for the region. This paper reports trends in extreme precipitation and temperature indices that were computed during the workshop and additional indices data that became available after the workshop. Trends in these indices were examined for 1950–2003 at 52 stations covering 15 countries, including Armenia, Azerbaijan, Bahrain, Cyprus, Georgia, Iran, Iraq, Israel, Jordan, Kuwait, Oman, Qatar, Saudi Arabia, Syria, and Turkey. Results indicate that there have been statistically significant, spatially coherent trends in temperature indices that are related to temperature increases in the region. Significant, increasing trends have been found in the annual maximum of daily maximum and minimum temperature, the annual minimum of daily maximum and minimum temperature, the number of summer nights, and the number of days where daily temperature has exceeded its 90th percentile. Significant negative trends have been found in the number of days when daily temperature is below its 10th percentile and daily temperature range. Trends in precipitation indices, including the number of days with precipitation, the average precipitation intensity, and maximum daily precipitation events, are weak in general and do not show spatial coherence. The workshop attendees have generously made the indices data available for the international research community.

On the robustness of the estimates of centennial‐scale variability in heavy precipitation from station data over Europe

The impact of missing values on the centennial‐scale variability of heavy precipitation was analysed using daily data from European rain gauges. Sub‐sampling was modeled according to the observed structure of gaps in daily precipitation records. Quantitative estimates of the sampling impact on the long‐term variability derived from high‐quality long‐term station data were used for the homogenization of sampling in European time series and the estimation of long‐term secular tendencies in heavy precipitation indices. Centennial linear trends of extreme precipitation based on different indices are quite robust in winter but less robust in summer, implying seasonality in the trend estimates especially in Western Europe. Estimates of annual indices derived for the locations where different indices shows significant trends imply primarily positive centennial‐scale changes in heavy and very heavy precipitation with the strongest magnitudes of about 3–5% per decade in Eastern Europe.

Recent trends in observed temperature and precipitation extremes in the Yangtze River basin, China

The present study is an analysis of the observed extreme temperature and precipitation trends over Yangtze from 1960 to 2002 on the basis of the daily data from 108 meteorological stations. The intention is to identify whether or not the frequency or intensity of extreme events has increased with climate warming over Yangtze River basin in the last 40 years. Both the Mann-Kendall (MK) trend test and simple linear regression were utilized to detect monotonic trends in annual and seasonal extremes.

North American Trends in Extreme Precipitation

An analysis of extreme precipitation events indicates that there has been a sizable increase in their frequency since the 1920s/1930s in the U.S. There has been no discernible trend in the frequency of the most extreme events in Canada, but the frequency of less extreme events has increased in some parts of Canada, notably in the Arctic. In the U.S., frequencies in the late 1800s/early 1900s were about as high as in the 1980s/1990s. This suggests that natural variability of the climate system could be the cause of the recent increase, although anthropogenic forcing due to increasing greenhouse gas concentrations cannot be discounted as another cause. It is likely that anthropogenic forcing will eventually cause global increases in extreme precipitation, primarily because of probable increases in atmospheric water vapor content and destabilization of the atmosphere. However, the location, timing, and magnitude of local and regional changes remain unknown because of uncertainties about future changes in the frequency/intensity of meteorological systems that cause extreme precipitation.