Frequency Distribution Of Precipitation Research Articles

Effects of changes in land use and land cover on sediment discharge of runoff in a typical watershed in the hill and gully loess region of northwest China

Land use plays a much more important role than other factors, such as climate, soil properties, topographic features, vegetation coverage, human activities and others, in affecting soil erosion and sediment discharge. In order to understand the effects of changes in land use on sediment discharge and to provide a theoretical basis for land use planning, management and ecological restoration, we used the controlled Qiaozidong watershed and the uncontrolled Qiaozixi watershed in the third sub-region of the Loess Plateau as examples and analyzed the effects of land use and land cover on the discharge of sediments. The results show that the impact of land use and land cover on the annual amount of sediment discharge is significant. Compared with the uncontrolled watershed during similar periods, the amount of sediment discharged from the controlled watershed was reduced by 44%, 75% and 86%, respectively, in wet, normal and dry years. In the controlled watershed, compared with the period from 1986 to 1994, the amount of sediments discharged was less during the period from 1995 to 2004. The impact of land use and land cover on sediment discharge demonstrated characteristics of seasonal fluctuation. The effects of sediment reduction in the controlled watershed were greater than those in the uncontrolled watershed in May and September. In the controlled watershed, the reduction effect coincided with the distribution of rainfall. The amount of discharged flood sediments is closely correlated with rainfall, rainfall intensity in a 60 min period and the volume of flood. The rainstorm-runoff process and the rainstorm-sediment discharge process demonstrate that land cover has a strong regulatory and control function in the flood process and sediment discharge in rainstorms. For the controlled watershed, given the same precipitation frequency distribution, the average amount of sediment discharged during the land use period from 1995 to 2004 was less than that during the earlier land use period from 1986 to 1994 under every recurrent period.

Atmospheric circulation patterns associated with extreme precipitation amounts in Greece

Abstract. The main synoptic conditions associated with extreme precipitation amounts in Greece are examined by using a multivariate statistical methodology comprising S-mode Factor Analysis and k-means Cluster Analysis. The following data were used : i) daily precipitation amounts (measured at 06:00 UTC) for the meteorological stations of Hellenikon (Athens), Thessaloniki (northern Greece) and Ioannina (western Greece) and ii) daily (18:00 UTC) 2.5×2.5 grid point values of 500 hPa geopotential height, mean sea-level pressure and 1000–500 hPa thickness at 273 grid points over Europe (10 W to 40 E and 30 N to 60 N), for the period 1970–2002. The dates corresponding to the upper 5% of the frequency distribution of precipitation are selected for each one of the three stations. In total, 369 dates are used, some of them being common among the three stations. The corresponding 369×273 data matrices of 500 hPa geopotential height, mean sea-level pressure and 1000–500 hPa thickness are constructed. The rows refer to the 369 extreme precipitation cases and the columns refer to the 273 grid points. The three matrices are unified into one 369×819 matrix. In order to reduce the dimensionality of the data set, S-mode Factor Analysis is applied to the unified matrix, revealing 7 factors accounting for 85% of the total variance. Finally, k-means Cluster Analysis is applied to the factor scores matrix, classifying the 369 cases into 9 clusters. For each one of the 9 clusters, the mean 18:00 UTC patterns of the above parameters are constructed and presented. These patterns correspond to the main distinct atmospheric circulation structures favoring extreme precipitation amounts in Greece. Most of the patterns are characterized by enhanced cyclonic activity over or near the Greek area. The differences among the 9 circulation structures refer mainly to the position and the intensity of the surface and the upper air synoptic systems involved. Some of the 9 synoptic conditions favor extreme precipitation amounts mainly at one or two of the three stations while some others equally affect the three stations.

How Often Will It Rain?

Abstract Daily precipitation data from climate change simulations using the latest generation of coupled climate system models are analyzed for potential future changes in precipitation characteristics. For the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) B1 (a low projection), A1B (a medium projection), and A2 (a high projection) during the twenty-first century, all the models consistently show a shift toward more intense and extreme precipitation for the globe as a whole and over various regions. For both SRES B1 and A2, most models show decreased daily precipitation frequency and all the models show increased daily precipitation intensity. The multimodel averaged percentage increase in the precipitation intensity (2.0% K−1) is larger than the magnitude of the precipitation frequency decrease (−0.7% K−1). However, the shift in precipitation frequency distribution toward extremes results in large increases in very heavy precipitation events (>50 mm day−1), so that for very heavy precipitation, the percentage increase in frequency is much larger than the increase in intensity (31.2% versus 2.4%). The climate model projected increases in daily precipitation intensity are, however, smaller than that based on simple thermodynamics (∼7% K−1). Multimodel ensemble means show that precipitation amount increases during the twenty-first century over high latitudes, as well as over currently wet regions in low- and midlatitudes more than other regions. This increase mostly results from a combination of increased frequency and intensity. Over the dry regions in the subtropics, the precipitation amount generally declines because of decreases in both frequency and intensity. This indicates that wet regions may get wetter and dry regions may become drier mostly because of a simultaneous increase (decrease) of precipitation frequency and intensity.

Hydrometeorological Analysis of the 29 August 2003 Flash Flood in the Eastern Italian Alps

Abstract The 29 August 2003 storm on the upper Tagliamento River basin in the eastern Italian Alps is examined as a prototype for organized convective systems that dominate the upper tail of the precipitation frequency distribution and are likely responsible for the majority of flash flood peaks in this area. The availability of high-resolution rainfall estimates from radar observations and rain gauge networks, together with flood response observations derived from stream gauge data and post-event surveys, provides the opportunity to study the hydrometeorological and hydrological mechanisms associated with this extreme storm and the associated flood. The flood occurred at the end of a climatic anomaly of prolonged drought and warm conditions over Europe and the Mediterranean region. A characteristic of the event is its organization in well-defined banded structures, some of which persisted in the same locations for the duration of the event. The steadiness of these rainbands led to highly variable precipitation accumulations and, associated with orographic enhancement, played a central role in the space–time organization of the storm. Two dominant controls on extreme flood response are recognized and analyzed: steadiness of convective bands and dry antecedent soil moisture conditions.

Performance of Quality Assurance Procedures on Daily Precipitation

Abstract The search for precipitation quality control (QC) methods has proven difficult. The high spatial and temporal variability associated with precipitation data causes high uncertainty and edge creep when regression-based approaches are applied. Precipitation frequency distributions are generally skewed rather than normally distributed. The commonly assumed normal distribution in QC methods is not a good representation of the actual distribution of precipitation and is inefficient in identifying the outliers. This paper first explores the use of a single gamma distribution, fit to all precipitation data, in a quality assurance test. A second test, the multiple intervals gamma distribution (MIGD) method, is introduced. It assumes that meteorological conditions that produce a certain range in average precipitation at surrounding stations will produce a predictable range at the target station. The MIGD bins the average of precipitation at neighboring stations; then, for the events in a specific bin, an associated gamma distribution is derived by fit to the same events at the target station. The new gamma distributions can then be used to establish the threshold for QC according to the user-selected probability of exceedance. This paper also explores a test (Q test) for precipitation, which uses a metric based on comparisons with neighboring stations. The performance of the three approaches is evaluated by assessing the fraction of “known” errors that can be identified in a seeded error dataset. The single gamma distribution and Q-test approach were found to be relatively efficient at identifying extreme precipitation values as potential outliers. However, the MIGD method outperforms the other two QC methods. This method identifies more seeded errors and results in fewer type I errors than the other methods. It will be adopted in the Applied Climatic Information System (ACIS) for precipitation quality control.

Downscaling from GCM precipitation: a benchmark for dynamical and statistical downscaling methods

A precipitation downscaling method is presented using precipitation from a general circulation model (GCM) as predictor. The method extends a previous method from monthly to daily temporal resolution. The simplest form of the method corrects for biases in wet-day frequency and intensity. A more sophisticated variant also takes account of flow-dependent biases in the GCM. The method is flexible and simple to implement. It is proposed here as a correction of GCM output for applications where sophisticated methods are not available, or as a benchmark for the evaluation of other downscaling methods. Applied to output from reanalyses (ECMWF, NCEP) in the region of the European Alps, the method is capable of reducing large biases in the precipitation frequency distribution, even for high quantiles. The two variants exhibit similar performances, but the ideal choice of method can depend on the GCM/reanalysis and it is recommended to test the methods in each case. Limitations of the method are found in small areas with unresolved topographic detail that influence higher-order statistics (e.g. high quantiles). When used as benchmark for three regional climate models (RCMs), the corrected reanalysis and the RCMs perform similarly in many regions, but the added value of the latter is evident for high quantiles in some small regions. Copyright © 2006 Royal Meteorological Society.

Variability of precipitation intensity: sensitivity to treatment of moist convection in an RCM and a GCM

The present study investigates the sensitivity of the frequency distribution of precipitation rates to the closure employed in the penetrative mass flux cumulus parameterization of Zhang and McFarlane in the Canadian regional climate model (CRCM) and in the Canadian Centre for Climate Modelling and Analysis third generation global atmospheric general circulation model (AGCM3). The effects of an alternative prognostic closure for mass flux cumulus parameterization in place of the original diagnostic closure are investigated. A set of experiments is performed in which changes in the frequency distribution of precipitation rates and cloud base mass-flux are examined as a function of the parameters that define each closure scheme. The relationship between the frequency distribution of precipitation and cloud base mass flux is examined and a self-consistent relation is found when the depth of convection is taken into account. Experiments performed with the prognostic closure favor relatively strong cloud base mass-flux and deep penetrative convection with relatively more intense convective precipitation. The mean of the frequency distribution of convective precipitation is larger and the heavier events become more intense. Also, experiments performed with the prognostic closure favor less frequent convective activity. However these changes in the distribution of convective component of precipitation are generally offset by opposite changes in the distribution of the resolved large-scale component of precipitation, resulting in relatively smaller changes in total precipitation. The altered partition of precipitation between convective and large-scale components is found to alter the energy balance and the thermodynamic equilibrium structure of the troposphere. The robustness found in the CRCM results regarding the sensitivity of the frequency distribution of precipitation to changes in the closure of the deep convection parameterization is investigated by performing a similar analysis of AGCM3 simulations. A remarkable similarity of AGCM3 and CRCM results is found suggesting that the closure sensitivity identified in this study is robust.

Projected Changes in Precipitation Characteristics around Japan under the Global Warming

A coupled ocean-atmosphere climate model is used to depict changes in precipitation characteristics around Japan in the 21st century. A comparison between high (T106 atmosphere) and medium (T42) resolution versions for the present-day climate shows that the higher resolution version better represents not only the mean but also the frequency distribution of precipitation. The climate projection for the 21st century by the high resolution version shows that mean precipitation increases more than 10% in 100 years from the present, especially in warm seasons. Increases in frequencies of non-precipitating and heavy (≥30 mm day-1) rainfall days and decrease in relatively weak (1-20 mm day-1) rainfall days are significant.

The relative impact of regional scale land cover change and increasing CO2 over China

A series of 17-yr equilibrium simulations using the NCAR CCM3 (T42 resolution) were performed to investigate the regional scale impacts of land cover change and increasing CO2 over China. Simulations with natural and current land cover at CO2 levels of 280, 355, 430, and 505 ppmv were conducted. Results show statistically significant changes in major climate fields (e.g. temperature and surface wind speed) on a 15-yr average following land cover change. We also found increases in the maximum temperature and in the diurnal temperature range due to land cover change. Increases in CO2 affect both the maximum and minimum temperature so that changes in the diurnal range are small. Both land cover change and CO2 change also impact the frequency distribution of precipitation with increasing CO2 tending to lead to more intense precipitation and land cover change leading to less intense precipitation—indeed, the impact of land cover change typically had the opposite effect versus the impacts of CO2. Our results provide support for the inclusion of future land cover change scenarios in long-term transitory climate modelling experiments of the 21st Century. Our results also support the inclusion of land surface models that can represent future land cover changes resulting from an ecological response to natural climate variability or increasing CO2. Overall, we show that land cover change can have a significant impact on the regional scale climate of China, and that regionally, this impact is of a similar magnitude to increases in CO2 of up to about 430 ppmv. This means that that the impact of land cover change must be accounted for in detection and attribution studies over China.

Fuzzy rule-based prediction of monthly precipitation

Monthly precipitation in Hungary is modeled using the Hess-Brezowsky atmospheric circulation pattern types and an ENSO index as forcing functions or inputs. The weakness of the statistical dependence between these individual inputs and precipitation prevents the use of a multivariate regression analysis for reproducing the probability distribution function of observed precipitation. In order to utilize the existing relationship between forcing functions and precipitation a fuzzy rule-based modeling technique is used. The first part of the observed input and precipitation data is used as the learning set to identify the fuzzy rules. Then, the second part of the data is used to validate the rules by comparing the frequency distributions of precipitation calculated respectively with the fuzzy rules and observed data. Example results are presented for two different climatic regions of Hungary. One of them represents a wetter climate while the other refers to the drier conditions of the Hungarian Plains. The fuzzy rule-based model reproduces the empirical frequency distributions in every season. However, as expected, the statistical prediction is better in winter, spring and fall than in the summer. The potential of the approach is important in climate change studies when the fuzzy rules obtained as described above can be used with input data stemming from GCM to predict regional/local precipitation reflecting GCM scenarios.

Seasonal and Regional Characteristics in the Frequency Distribution of Precipitation

The frequency distribution of precipitation changes from inverse J-shaped type, through the exponential, to normal type with increase in a length of lumped period. The seasonal and regional characteristics of the change with lumped period from 1 hour to 30 days are investigated for AMeDAS precipitation data sets. The gamma distribution is employed as a distribution model fitted to the observed data and the method of maximum-entropy as a method of the parameter estimation. The shape of a frequency distribution can be expressed quantitatively by the information content due to logarithmic geometric mean. The following findings are drawn from the frequency analysis: 1) Lumped period in which a frequency distribution is the exponential one for winter-half-year is rather short on the Japan Sea side and rather long on the Pacific Ocean side. The regional difference is understood by considering that main precipitation-induced disturbance is different for each region and each disturbance has its own time-series characteristics. 2) As for variation of information content due to logarithmic geometric mean in short-term, there is latitudinal difference in the Japanese Islands, which corresponds with difference between precipitation characteristics represented by rain shower and those by continuous rain.

降水量の度数分布にみられる時間特性とその地域的・局地的特徴

降水量の度数分布は,集計する時間単位が長くなるにしたがって逆J字型・指数・正規型と変化する.1時間から30日間にわたる,この変化の地域的・局地的特徴を,暖候期について,日本全国を対象としたAMeDASデータを用いて調べた.分布のあてはめには,分布モデルと統計量が一対一の対応をする最大エントロピー法を用い,分布の形状を量的ばらつき(対数幾何平均)のもつ情報量によって定量化した.その結果,度数分布は平均10日間で指数分布となり,指数分布となる集計時間の地理的分布には地域的なまとまりがみられる.短時間降水量に対しては,量的ばらつきを地理的分布からみると,地形が関係した局地性が認められ,地形性上昇域で量的ばらつきが大きい.また,集計時間が大雨の持続時間に一致するとき量的ばらつきは最大となるので,地形性上昇による大雨の持続時間を統計的に求めることができ,その値は12時間程度である.

Anticipating the frequency distribution of precipitation if climate change alters its mean

The relationship between the shape and dispersion of the frequency distributions of precipitation amounts and their means among present climates gives a clue as to how the probabilities of extremes will change if the mean changes. The distribution is limited at zero and, as the means decrease, the standard deviations decrease and the distributions become more skewed. The gamma distribution function fits these distributions from the nearly normal of annual amounts in humid climates to the skewed of monthly in arid ones. Its mean, M, is BG and variance, V, is B 2 G, where B is the scale and G the shape parameter. Among 660 cases of 12 monthly distributions at 55 diverse stations, the variance increased as M 1.3 ( r 2=0.90), which specifies relationships between the mean and B and G. Thus, probabilities are specified by the mean and among 660 cases, 572 specified probabilities of amounts less than half the mean were not significantly different from observed. For precipitation more than three halves the mean, 653 were not significantly different from observed. The relationships among parameters specify a dimensionless elasticity or relative increase in the probability of extremes with a relative decrease in the mean. For amounts below a threshold, the elasticity is greater for lower thresholds and higher means, and it is often >1, signifying a relatively greater rise in the probability of extremes than a fall in the mean.

Comment on ‘Some comparisons of flood statistics in real and log space’ by J. Maciunas Landwehr, N. C. Matalas, and J. R. Wallis

Water Resources ResearchVolume 15, Issue 4 p. 979-981 CommentariesFree Access Comment on ‘Some comparisons of flood statistics in real and log space’ by J. Maciunas Landwehr, N. C. Matalas, and J. R. Wallis Krishan P. Singh, Krishan P. SinghSearch for more papers by this author Krishan P. Singh, Krishan P. SinghSearch for more papers by this author First published: August 1979 https://doi.org/10.1029/WR015i004p00979Citations: 2AboutReferencesRelatedInformationPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessClose modalShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. References Anderson, D. V., Review of basic concepts in hydrology, Statistical Methods in Hydrology, Proceedings of the Fifth Hydrology Symposium, 3– 27, Department of Energy, Mines and Resources, Ottawa, Canada, 1966. Box, G. E. P., M. E. Mueller, A note on the generation of random normal deviates, Ann. Math. Statist., 29, 610– 681, 1958. Cohen, A. C., Estimation in mixtures of two normal distributions, Technometrics, 91, 15– 28, 1967. Essenwanger, O., Frequency distributions of precipitation, Physics of Precipitation, Geophys. Monogr. Ser., 5 H. Weickmann, 271– 278, AGU, Washington, D. C., 1960. Hawkins, R. H., A note on mixed distributions in hydrology, Proceedings of the Symposium on Statistical Hydrology, U.S. Dep. Agr. Misc. Publ., 1275, 336– 344, 1974. Hiser, H. H., Type distributions of precipitations at selected stations in Illinois, Eos Trans. AGU, 37, 421– 424, 1956. Landwehr, J. M., N. C. Matalas, J. R. Wallis, Some comparisons of flood statistics in real and log space, Water Resour. Res., 145, 902– 920, 1978. Singh, K. P., Hydrologic distributions resulting from mixed populations and their computer simulation, Int. Ass. Sci. Hydrol. Publ., 81, 671– 681, 1968. Singh, K. P., Role of baseflow in rainfall-runoff relations, Water Resour. Bull., 84, 813– 824, 1972. Singh, K. P., Two-distribution method for fitting mixed distributions in hydrology, Proceedings of the Symposium on Statistical Hydrology, U.S. Dep. Agr. Misc. Publ., 1275, 371– 382, 1974. Singh, K. P., C. G. Lonnquist, Two-distribution method for modeling and sequential generation of monthly streamflows, Water Resour. Res., 104, 763– 773, 1974. Singh, K. P., R. A. Sinclair, Two-distribution method for flood-frequency analysis, J. Hydraul. Div. Amer. Soc. Civil Eng., 98HYI, 29– 44, 1972. Citing Literature Volume15, Issue4August 1979Pages 979-981 ReferencesRelatedInformation RecommendedReply [to “Comment on ‘Some comparisons of flood statistics in real and log space’ by J. Maciunas Landwehr, N. C. Matalas, and J. R. Wallis”]J. Maciunas Landwehr, N. C. Matalas, J. R. Wallis, Water Resources ResearchSome comparisons of flood statistics in real and log spaceJ. Maciunas Landwehr, N. C. Matalas, J. R. Wallis, Water Resources ResearchComment on “Quantile Estimation With More or Less Floodlike Distributions” by J. M. Landwehr, N. C. Matalas, and J. R. WallisJorge Machado Damázio, Water Resources ResearchReply [to “Comments on ‘Correlogram analysis revisited’ by J. R. Wallis and N. C. Matalas”]J. R. Wallis, N. C. Matalas, Water Resources ResearchComment on ‘Regional skew in search of a parent’ by N. C. Matalas, J. R. Slack, and J. R. WallisV. Klemes, Water Resources Research

Precipitation characteristics during the Venezuela rainy season

AbstractAn extensive program of observations designed to determine the structure of tropical mesoscale rain areas over land and their relation to synoptic envelopes was carried out during the rainy season of 1969 (June to September) in eastern Venezuela.The frequency distribution of precipitation in the area seen by radar (radius 100 km), as given by the average of 30 stations, was highly skewed: 14 per cent of the days in the experiment delivered half of the precipitation; 80 per cent could be attributed to rain episodes related to mobile synoptic systems. On the hourly basis, 0·45 per cent of all hours (or 10 hours) produced half of the precipitation.Daily precipitation in the radar circle was not correlated with radar echo height but markedly with echo area. Heavy rainfall occurs when a few very large clouds appear.A cloud distribution in terms of area and rain productiveness was determined for rainy and for dry days. Rain productivity increases with cloud area; however, since the number of clouds also decreases as their size increases, water yield to the ground is almost independent of cloud scale. No clear difference in the 200 mb flow could be found between cloud ensemble.On rainy days the temperature is lower and the specific humidity higher than on dry days confirming that cold‐core precipitation takes place also over Venezuela. A mean ascending velocity appears to exist in and out of clouds in the convection cores, but could not be found prior to onset of afternoon convection.

NATURE AND POSSIBLE CAUSES OF THE NORTHEASTERN UNITED STATES DROUGHT DURING 1962–65

Abstract During the past 4 years noteworthy weather fluctuations of a persistent kind have occurred over large portions of the United States, the most prominent, of which have been the deficiency in precipitation over the Northeast and the excess over the Southwest and the Northern Plains. The nature of these abnormalities is described with the help of seasonal frequency distributions of precipitation determined for 40 climatologically homogeneous areas of the country. From this and other material it is shown that the Northeast drought has been largely a spring and summer phenomenon at the same time when abundant rains occurred over the Northern Plains and Far Southwest. The large-scale upper-air currents favoring or inhibiting precipitation through interactions with air masses and storms are next described. The most consistent year-to-year feature of these upper winds in the quadrennial has been the persistence of one southward dip in the westerlies just off the eastern seaboard and another over the Far ...

Relation between precipitation deficiency and low streamflow

A study was made to determine whether low-flow frequency distributions in Illinois could be reliably estimated from meteorological data and geologic factors. The development of such a method is desirable because of the general lack of long-term streamflow records. In this study, use was made of 50-year records of precipitation from 62 locations and data from 12 stream-gage stations with 45-year or longer records. When the state was divided into six different geomorphic regions it was found that the low-flow frequencies for any basin in each region could be reliably estimated by the precipitation frequency distribution and a geomorphic index. The regional geomorphic indices were developed through use of data from the 12 basins with long streamflow records. The method developed is applicable for basins of any size, for recurrence intervals of five years or longer, and for drought durations of 12 months or longer. Although based upon Illinois data, the method should be applicable to other regions in the United States and other parts of the world.

Linear and logarthmic scale for frequency distribution of precipitation

The linear scale is often used for frequency distributions of precipitation data. The statistical approach for these distributions is briefly discussed and compared with results obtained using a logarithmic scale. The latter permits a frequency analysis and resolution in partial collectives, which furnishes a more precise climatological description and understanding of precipitation frequency. Fifty years of Asheville, North Carolina, precipitation records (yearly, monthly, daily, six-hourly, hourly amount) serve as a sample.