Let-It-Rain: a web application for stochastic point rainfall generation at ungaged basins and its applicability in runoff and flood modeling

  • Dongkyun KimEmail author
  • Huidae Cho
  • Christian Onof
  • Minha Choi
Original Paper


We present a web application named Let-It-Rain that is able to generate a 1-h temporal resolution synthetic rainfall time series using the modified Bartlett–Lewis rectangular pulse (MBLRP) model, a type of Poisson stochastic rainfall generator. Let-It-Rain, which can be accessed through the web address, adopts a web-based framework combining ArcGIS Server from server side for parameter value dissemination and JavaScript from client side to implement the MBLRP model. This enables any desktop and mobile end users with internet access and web browser to obtain the synthetic rainfall time series at any given location at which the parameter regionalization work has been completed (currently the contiguous United States and Republic of Korea) with only a few mouse clicks. Let-It-Rain shows satisfactory performance in its ability to reproduce observed rainfall mean, variance, auto-correlation, and probability of zero rainfall at hourly through daily accumulation levels. It also shows a reasonably good performance in reproducing watershed runoff depth and peak flow. We expect that Let-It-Rain can stimulate the uncertainty analysis of hydrologic variables across the world.


Poisson cluster rainfall simulation Modified Bartlett–Lewis rectangular pulse model Neyman–Scott rectangular pulse model Rainfall disaggregation Rainfall downscaling Climate change 



This research was supported by the Basic Research Laboratory Program (50 %, Grant ID: NRF-2015041523) and by the Basic Science Research Program (50 %, Grant ID: NRF-2013R1A1A1011676) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  • Dongkyun Kim
    • 1
    Email author
  • Huidae Cho
    • 2
  • Christian Onof
    • 3
  • Minha Choi
    • 4
  1. 1.Department of Civil EngineeringHongik UniversitySeoulRepublic of Korea
  2. 2.DewberryAtlantaUSA
  3. 3.Department of Civil and Environmental EngineeringImperial CollegeLondonUK
  4. 4.Water Resources and Remote Sensing Laboratory, Department of Water Resources, Graduate School of Water ResourcesSungkyunkwan UniversitySuwonRepublic of Korea

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