Dynamical and Thermodynamical Interactions in Daily Precipitation Regimes in the Western Himalayas

2021 ◽  
Author(s):  
Suma Bhanu Battula ◽  
Steven Siems ◽  
Arpita Mondal
Keyword(s):  
Daily Precipitation ◽  
Western Himalayas ◽  
Precipitation Regimes

scholarly journals Complexity and predictability of daily precipitation in a semi-arid region: an application to Ceará, Brazil

2006 ◽  
Vol 13 (6) ◽  
pp. 651-659 ◽  
Author(s):  
M. E. S. Silva ◽  
L. M. V. Carvalho ◽  
M. A. F. da Silva Dias ◽  
T. de M. B. S. Xavier
Keyword(s):  
Arid Region ◽  
Daily Precipitation ◽  
Large Degree ◽  
Inter Tropical Convergence Zone ◽  
Periodic Sequences ◽  
Precipitation Regimes ◽  
Ocean Topography ◽  
Semi Arid Region ◽  
Precipitation Records ◽  
Semi Arid

Abstract. Complexity and predictability of daily precipitation in a tropical semi-arid region (Ceará State, Brazil) is assessed by applying entropy concepts. Precipitation regimes in that region depend on several dynamical forcings, the most important being the displacement and activity of the Inter-tropical Convergence Zone in the Atlantic Ocean. Topography is another important factor that influences the spatial distribution of rainfall in the region. A hierarchical approach based on sequences of events of different lengths is used to estimate complexity of daily precipitation records. It is shown that precipitation in Ceará exhibit more random than periodic sequences, which indicates a large degree of complexity. Nevertheless, there is indication of potentially inherent rules in the precipitation time-series that could ultimately improve prediction on time-scales between 9–11 days. It is suggested that synoptic-scale disturbances (1–8 days) represent important sources of rules in the precipitation regimes in this region.

scholarly journals Influence of three phases of El Niño–Southern Oscillation on daily precipitation regimes in China

2019 ◽  
Vol 23 (2) ◽  
pp. 883-896 ◽  
Author(s):  
Aifeng Lv ◽  
Bo Qu ◽  
Shaofeng Jia ◽  
Wenbin Zhu
Keyword(s):  
El Niño ◽  
Daily Precipitation ◽  
El Nino ◽  
Southern Oscillation ◽  
Annual Precipitation ◽  
Rainfall Events ◽  
Enso Events ◽  
Precipitation Regimes ◽  
Precipitation Anomalies ◽  
Three Phases

Abstract. In this study, the impacts of the El Niño–Southern Oscillation (ENSO) on daily precipitation regimes in China are examined using data from 713 meteorological stations from 1960 to 2013. We discuss the annual precipitation, frequency and intensity of rainfall events, and precipitation extremes for three phases (eastern Pacific El Niño – EP, Central Pacific El Niño – CP, and La Niña – LN) of ENSO events in both ENSO developing and ENSO decaying years. A Mann–Whitney U test was applied to assess the significance of precipitation anomalies due to ENSO. Results indicated that the three phases each had a different impact on daily precipitation in China and that the impacts in ENSO developing and decaying years were significantly different. EP phases caused less precipitation in developing years but more precipitation in decaying years; LN phases caused a reverse pattern. The precipitation anomalies during CP phases were significantly different than those during EP phases, and a clear pattern was found in decaying years across China, with positive anomalies over northern China and negative anomalies over southern China. Further analysis revealed that anomalies in frequency and intensity of rainfall accounted for these anomalies in annual precipitation; in EP developing years, negative anomalies in both frequency and intensity of rainfall events resulted in less annual precipitation, while in CP decaying years, negative anomalies in either frequency or intensity typically resulted in reduced annual precipitation. ENSO events tended to trigger extreme precipitation events. In EP and CP decaying years and in LN developing years, the number of very wet day precipitation (R95 p), the maximum rainfall in 1 day (Rx1d), and the number of consecutive wet days (CWD) all increased, suggesting an increased risk of flooding. On the other hand, more dry spells (DSs) occurred in EP developing years, suggesting an increased likelihood of droughts during this phase. Possible mechanisms responsible for these rainfall anomalies are speculated to be the summer monsoon and tropical cyclone anomalies in ENSO developing and decaying years.

scholarly journals Seasonality of runoff and precipitation regimes along transects in Peru and Austria

2017 ◽  
Vol 65 (4) ◽  
pp. 347-358 ◽  
Author(s):  
Maria M. Cárdenas Gaudry ◽  
Dieter Gutknecht ◽  
Juraj Parajka ◽  
Rui A.P. Perdigão ◽  
Günter Blöschl
Keyword(s):  
Spatial Variation ◽  
Extreme Precipitation ◽  
Daily Precipitation ◽  
Circular Statistics ◽  
Monthly Precipitation ◽  
Annual Maximum ◽  
Discharge Data ◽  
Precipitation Regimes ◽  
Daily Precipitation Data ◽  
Monthly Runoff

AbstractThe aim of this study is to understand the seasonalities of runoff and precipitation and their controls along two transects in Peru and one transect in Austria. The analysis is based on daily precipitation data at 111 and 61 stations in Peru and Austria, respectively, and daily discharge data at 51 and 110 stations. The maximum Pardé coefficient is used to quantify the strength of the seasonalities of monthly precipitation and runoff. Circular statistics are used to quantify the seasonalities of annual maximum daily precipitation and annual maximum daily runoff. The results suggest that much larger spatial variation in seasonality in Peru is because of the large diversity in climate and topography. In the dry Peruvian lowlands of the North, the strength of the monthly runoff seasonality is smaller than that of precipitation due to a relatively short rainy period from January to March, catchment storage and the effect of upstream runoff contributions that are more uniform within the year. In the Peruvian highlands in the South, the strength of the monthly runoff seasonality is greater than that of precipitation, or similar, due to relatively little annual precipitation and rather uniform evaporation within the year. In the Austrian transect, the strength of the runoff seasonality is greater than that of precipitation due to the influence of snowmelt in April to June. The strength of monthly regime of precipitation and runoff controls the concentration of floods and extreme precipitation in Peruvian transects. The regions with strong monthly seasonality of runoff have also extreme events concentrated along the same time of the year and the occurrence of floods is mainly controlled by the seasonality of precipitation. In Austria, the monthly runoff maxima and floods occur in the same season in the Alps. In the lowlands, the flood seasonality is controlled mainly by summer extreme precipitation and its interplay with larger soil moisture. The analyses of precipitation and runoff data along topographic gradients in Peru and Austria showed that, overall, in Peru the spatial variation in seasonality is much larger than in Austria. This is because of the larger diversity in climate and topography.

scholarly journals Modelling the frequency distribution of inter-arrival times from daily precipitation time-series in North-West Italy

2018 ◽  
Vol 50 (1) ◽  
pp. 339-357 ◽  
Author(s):  
Giorgio Baiamonte ◽  
Luca Mercalli ◽  
Daniele Cat Berro ◽  
Carmelo Agnese ◽  
Stefano Ferraris
Keyword(s):  
Time Series ◽  
Frequency Distribution ◽  
Daily Precipitation ◽  
Regional Scale ◽  
Precipitation Time Series ◽  
Precipitation Regime ◽  
Arrival Times ◽  
North West ◽  
Pettitt Test ◽  
Precipitation Regimes

Abstract The discrete three-parameter Lerch distribution is used to analyse the frequency distribution of inter-arrival times derived from 26 daily precipitation time-series, collected by stations located throughout a 28,000 km2 area in North-West Italy (altitudes ranging from 113 m to 2,170 m a.s.l.). The precipitation regime of these Alpine regions is very different (latitude 44.5 to 46.5 N) from the typical Mediterranean precipitation regime of the island of Sicily (latitude 37 to 38 N), where the Lerch distribution has already been tested and whose results are compared. In order to verify the homogeneity of the precipitation time series, the Pettitt test was preliminarily performed. In this work, a good fitting of the Lerch distribution to NW Italy is shown, thus evidencing the wide applicability of this kind of distribution, also allowing to jointly model dry spells and wet spells. The three parameters of the Lerch distribution showed rather different values than the Sicily ones, likely due to the very different precipitation regimes. Finally, a relevant spatial variability of inter-arrival times in the study area was revealed from the regional scale application of the probability distribution here described. The outcomes of this study could be of interest in different hydrologic applications.

scholarly journals A Novel Combined Model for Prediction of Daily Precipitation Data using Instantaneous Frequency Feature and Bidirectional Long Short Time Memory Networks

2021 ◽  
Author(s):  
Levent Latifoğlu
Keyword(s):  
Instantaneous Frequency ◽  
Daily Precipitation ◽  
Human Life ◽  
Absolute Error ◽  
Precipitation Data ◽  
Precipitation Forecasting ◽  
Precipitation Regimes ◽  
Daily Precipitation Data ◽  
Long Time ◽  
Short Time

Abstract In the developing world, to learn nature better, to get the maximum benefit from nature is being studied. Meteorological events constantly affect human life. The occurrence of excessive precipitation in a short time causes important events such as floods. However, in case of insufficient precipitation for a long time, drought occurs. In recent years, significant changes in precipitation regimes have been observed and these changes cause socioeconomic and ecological problems. Therefore, it is of great importance to correctly predict and analyze these variables. In this study, reliable and accurate precipitation forecasting model is proposed. Ensemble of instantaneous frequency (IF) Bidirectional Long Short Time Memory Networks (biLSTM) model was employed for the aim of forecasting of daily precipitation data. To compare the performance of biLSTM model, Long Short Time Memory Networks (LSTM) and Gated Recurrent Unit (GRU) model was applied for forecasting of daily precipitation data. The performance of the proposed IF-biLSTM model was evaluated using Mean absolute error (MAE), Mean square Error (MSE), Correlation Coefficient (R) and Determination Coefficient (R2) performance parameter. According to numerical results, IF-biLSTM model has the best forecasting performance for daily precipitation data. Especially six ahead precipitation forecasting is noteworthy.

scholarly journals Influence of three phases of El Niño-Southern Oscillation on daily precipitation regimes in China

2018 ◽  
Author(s):  
Aifeng Lv ◽  
Bo Qu ◽  
Shaofeng Jia ◽  
Wenbin Zhu
Keyword(s):  
El Niño ◽  
Daily Precipitation ◽  
El Nino ◽  
Southern Oscillation ◽  
Annual Precipitation ◽  
Rainfall Events ◽  
Enso Events ◽  
Precipitation Regimes ◽  
Precipitation Anomalies ◽  
Three Phases

Abstract. In this study, the impacts of the El Niño-Southern Oscillation (ENSO) on daily precipitation regimes in China are examined using data from 713 meteorological stations from 1960 to 2013. We discuss the annual precipitation, frequency and intensity of rainfall events, and precipitation extremes for three phases (Eastern Pacific El Niño (EP), Central Pacific El Niño (CP), and La Niña (LN)) of ENSO events in both ENSO developing and ENSO decaying years. A Mann–Whitney U test was applied to assess the significance of precipitation anomalies due to ENSO. Results indicated that the three phases each had a different impact on daily precipitation in China and that the impacts in ENSO developing and decaying years were significantly different. EP phases caused less precipitation in developing years but more precipitation in decaying years; LN phases caused a reverse pattern. The precipitation anomalies during CP phases were significantly different than those during EP phases and a clear pattern was found in decaying years across China, with positive anomalies over northern China and negative anomalies over southern China. ENSO events which altered the frequency and intensity of rainfall roughly paralleled anomalies in annual precipitation; in EP developing years, negative anomalies in both frequency and intensity of rainfall events resulted in less annual precipitation while in CP decaying years, negative anomalies in either frequency or intensity typically resulted in reduced annual precipitation. ENSO events triggered more extreme precipitation events. In EP and CP decaying years and in LN developing years, the number of very wet days (R95p), the maximum rainfall in one day (Rx1d), and the number of consecutive wet days (CWD) all increased, suggesting an increased risk of flooding. In addition, more dry spells (DS) occurred in EP developing years, suggesting an increased likelihood of droughts during this phase.

scholarly journals Isotopic composition of daily precipitation along the southern foothills of the Himalayas: impact of marine and continental sources of atmospheric moisture

2018 ◽  
Vol 18 (12) ◽  
pp. 8789-8805 ◽  
Author(s):  
Ghulam Jeelani ◽  
Rajendrakumar D. Deshpande ◽  
Michal Galkowski ◽  
Kazimierz Rozanski
Keyword(s):  
Isotopic Composition ◽  
Daily Precipitation ◽  
Isotope Composition ◽  
Himalayan Region ◽  
Water Evaporation ◽  
Western Himalayas ◽  
Atmospheric Moisture ◽  
Air Masses ◽  
Continental Origin ◽  
The Impact

Abstract. The flow of the Himalayan rivers, a key source of fresh water for more than a billion people primarily depends upon the strength, behaviour and duration of the Indian summer monsoon (ISM) and the western disturbances (WD), two contrasting circulation regimes of the regional atmosphere. An analysis of the 2H and 18O isotope composition of daily precipitation collected along the southern foothills of the Himalayas, combined with extensive backward trajectory modelling, was used to gain deeper insight into the mechanisms controlling the isotopic composition of precipitation and the origin of atmospheric moisture and precipitation during ISM and WD periods. Daily precipitation samples were collected during the period from September 2008 to December 2011 at six stations, extending from Srinagar in the west (Kashmir state) to Dibrugarh in the east (Assam state). In total, 548 daily precipitation samples were collected and analysed for their stable isotope composition. It is suggested that the gradual reduction in the 2H and 18O content of precipitation in the study region, progressing from δ18O values close to zero down to ca. −10 ‰ in the course of ISM evolution, stems from regional, large-scale recycling of moisture-driven monsoonal circulation. Superimposed on this general trend are short-term fluctuations of the isotopic composition of rainfall, which might have stem from local effects such as enhanced convective activity and the associated higher degree of rainout of moist air masses (local amount effect), the partial evaporation of raindrops, or the impact of isotopically heavy moisture generated in evapotranspiration processes taking place in the vicinity of rainfall sampling sites. Seasonal footprint maps constructed for three stations representing the western, central and eastern portions of the Himalayan region indicate that the influence of monsoonal circulation reaches the western edges of the Himalayan region. While the characteristic imprint of monsoonal air masses (increase of monthly rainfall amount) can be completely absent in the western Himalayas, the onset of the ISM period in this region is still clearly visible in the isotopic composition of daily precipitation. A characteristic feature of daily precipitation collected during the WD period is the gradual increase of 2H and 18O content, reaching positive δ2H and δ18O values towards the end of the period. This trend can be explained by the growing importance of moisture of continental origin as a source of daily precipitation. High deuterium-excess (d-excess) values of daily rainfall recorded at the monitoring stations (38 cases in total, range from 20.6 to 44.0 ‰) are attributed to moisture of continental origin released into the atmosphere during the evaporation of surface water bodies and/or soil water evaporation.

scholarly journals New Techniques for the Detection and Adjustment of Shifts in Daily Precipitation Data Series

2010 ◽  
Vol 49 (12) ◽  
pp. 2416-2436 ◽  
Author(s):  
Xiaolan L. Wang ◽  
Hanfeng Chen ◽  
Yuehua Wu ◽  
Yang Feng ◽  
Qiang Pu
Keyword(s):  
Daily Precipitation ◽  
Precipitation Amount ◽  
Data Series ◽  
Precipitation Series ◽  
Precipitation Data ◽  
Transformation Procedure ◽  
Precipitation Regimes ◽  
Daily Precipitation Data ◽  
Non Gaussian ◽  
Gaussian Data

Abstract This study integrates a Box–Cox power transformation procedure into a common trend two-phase regression-model-based test (the extended version of the penalized maximal F test, or “PMFred,” algorithm) for detecting changepoints to make the test applicable to non-Gaussian data series, such as nonzero daily precipitation amounts or wind speeds. The detection-power aspects of the transformed method (transPMFred) are assessed by a simulation study that shows that this new algorithm is much better than the corresponding untransformed method for non-Gaussian data; the transformation procedure can increase the hit rate by up to ∼70%. Examples of application of this new transPMFred algorithm to detect shifts in real daily precipitation series are provided using nonzero daily precipitation series recorded at a few stations across Canada that represent very different precipitation regimes. The detected changepoints are in good agreement with documented times of changes for all of the example series. This study clarifies that it is essential for homogenization of daily precipitation data series to test the nonzero precipitation amount series and the frequency series of precipitation occurrence (or nonoccurrence), separately. The new transPMFred can be used to test the series of nonzero daily precipitation (which are non Gaussian and positive), and the existing PMFred algorithm can be used to test the frequency series. A software package for using the transPMFred algorithm to detect shifts in nonzero daily precipitation amounts has been developed and made freely available online, along with a quantile-matching (QM) algorithm for adjusting shifts in nonzero daily precipitation series, which is applicable to all positive data. In addition, a similar QM algorithm has also been developed for adjusting Gaussian data such as temperatures. It is noticed that frequency discontinuities are often inevitable because of changes in the measuring precision of precipitation, and that they could complicate the detection of shifts in nonzero daily precipitation data series and void any attempt to homogenize the series. In this case, one must account for all frequency discontinuities before attempting to adjust the measured amounts. This study also proposes approaches to account for detected frequency discontinuities, for example, to fill in the missed measurements of small precipitation or the missed reports of trace precipitation. It stresses the importance of testing the homogeneity of the frequency series of reported zero precipitation and of various small precipitation events, along with testing the series of daily precipitation amounts that are larger than a small threshold value, varying the threshold over a set of small values that reflect changes in measuring precision over time.

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