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Precipitation Records (precipitation + record)

Distribution by Scientific Domains

Engineering	33%

Selected Abstracts

Pilot study of latewood-width of conifers as an indicator of variability of summer rainfall in the North American monsoon region

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 6 2001
David M. Meko
Abstract The variability of the North American Monsoon System (NAMS) is important to the precipitation climatology of Mexico and the southwestern United States. Tree-ring studies have been widely applied to climatic reconstruction in western North America, but as yet, have not addressed the NAMS. One reason is the need for highly resolved seasonal dendroclimatic information. Latewood-width, the portion of the annual tree ring laid down late in the growing season, can potentially yield such information. This paper describes a pilot study of the regional summer precipitation signal in latewood-width from a network of five Pseudotsuga menziesii chronologies developed in the heart of the region of NAMS influence in Arizona, USA. Exploratory data analysis reveals that the summer precipitation signal in latewood is strong, but not equally so over the full range of summer precipitation. Scatter in the relationship increases toward higher levels of precipitation. Adjustment for removal of inter-correlation with earlywood-width appears to strengthen the summer precipitation signal in latewood-width. To demonstrate a possible application to climatic reconstruction, the latewood precipitation signal is modelled using a nonlinear model,a binary recursive classification tree (CT) that attempts to classify summers as dry or not dry from threshold values of latewood-width. The model identifies narrow latewood-width as an effective predictor of a dry summer. Of 14 summers classified dry by latewood-width for the period 1868,1992, 13 are actually dry by the instrumental precipitation record. The results suggest that geographical expansion of coverage by latewood-width chronologies and further development of statistical methods may lead to successful reconstruction of variability of the NAMS on century time scales. Copyright © 2001 Royal Meteorological Society [source]

Long-term trend analysis for precipitation in Asian Pacific FRIEND river basins

HYDROLOGICAL PROCESSES, Issue 18 2005
Z. X. Xu
Abstract In order to analyse the long-term trend of precipitation in the Asian Pacific FRIEND region, records from 30 river basins to represent the large range of climatic and hydrological characteristics in the study area are selected. The long-term trend in precipitation time series and its association with the southern oscillation index (SOI) series are investigated. Application of the nonparametric Mann,Kendall test for 30 precipitation time series has shown that only four of these 30 time series have a long-term trend at the 5% level of significance. Nevertheless, most of the records tend to decrease over the last several decades. The dataset is further divided geographically into northern, middle, and southern zones, with 20°N and 20°S latitude as the dividing lines. The middle zone has the greatest variation and the southern zone the least variation over the past century. Also, the southern zone has greater variation during the past 30 years. The association between precipitation and SOI is investigated by dividing the precipitation records of each station into El Niño, La Niña, and neutral periods. The Wilcoxon rank-sum test showed that differences in precipitation for the three classes were most marked in the southern zone of the study area. The frequencies of below- and above-average precipitation for El Niño, La Niña, and neutral periods are estimated for the 30 precipitation time series as well. The results show that the frequencies of precipitation under each set of conditions, with lower precipitation generally associated with El Niño periods in the southern zone. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Trends in the boreal summer regional Hadley and Walker circulations as expressed in precipitation records from Asia and Africa during the latter half of the 20th century

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 5 2008
Hongxu Zhao
Abstract West African summer rainfall, north China summer rainfall and a new climate proxy, snow accumulation from the Dasuopu ice core in the southern Himalaya, have all experienced decreasing trends during the latter half of the 20th century. In this paper, we investigate the existence of a common mechanism that explains these geographically dispersed trends during the boreal summer. In particular, we explore the hypothesis that these trends are related to changes in the regional Hadley and Walker circulations. We show that the divergent circulation in the NCEP reanalysis indicates the existence of trends in these circulations that are consistent with the observed changes in the precipitation records. In addition, the regressions of the divergent circulation in the NCEP reanalysis against these precipitation records indicate that a similar globally coherent signal is associated with the time series and their linear trends while the regressions against the de-trended residuals do not contain statistically significant large-scale signals. These similarities lead us to conclude that the decreasing trends in the three precipitation time series during the latter half of the 20th century are consistent with large-scale changes in the global overturning circulation during the boreal summer. Copyright © 2007 Royal Meteorological Society [source]

Lagged teleconnections between snow depth in northern Eurasia, rainfall in Southeast Asia and sea-surface temperatures over the tropical Pacific Ocean

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 13 2001
Hengchun Ye
Abstract This study shows that above-(below-)normal winter snow depth over European Russia and corresponding below-(above-)normal snow depth over central Siberia is associated with reduced (increased) summer monsoon rainfall over southern and western India and eastern Pakistan, and above-(below-)normal sea-surface temperatures (SSTs) over the eastern and central tropical Pacific Ocean during the following winters. The connection is slightly stronger when snow depth over European Russia is above normal than below normal. These results are derived from an examination of 60 years (1936,1995) of winter snow depth data and SSTs, and 45 years (1951,1995) of summer precipitation records. The results of this study suggest that winter snow depth over the western rather than the eastern portion of Eurasia is critical to Southeast Asian summer monsoon rainfall and eastern tropical Pacific SSTs during the following seasons. Copyright © 2001 Royal Meteorological Society [source]

Rain rate conversion for various integration time for equatorial and tropical climates

INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING, Issue 4 2008
J. S. Mandeep
Abstract Rain rate statistics are derived on the basis of rain gauge recordings having effective integration times of 5,min or more. The conversion of such data to equivalent statistics for an effective integration time of 1,min is important to the design of both terrestrial and earth-space microwave systems. Tipping bucket precipitation records for seven locations in South East Asia countries have been analysed and present the results of a testing activity performed on four conversion methods of rain rate integration time, from 5, 10, 30 and 60 to 1,min. Copyright © 2008 John Wiley & Sons, Ltd. [source]