Skip to content

Latest commit

 

History

History
91 lines (66 loc) · 6.74 KB

README.md

File metadata and controls

91 lines (66 loc) · 6.74 KB
Raw

Satellite Precipitation Products Download

Daniel Althoff

About

Satellite Precipitation Products Download (SPP-Down) is an App developed with Shiny to download Precipitation Measuring Missions datasets from the Goddard Earth Sciences Data and Information Services Center (GES DISC).

The main goal of the SPP-Down is to help people that are not proficient in programmming to download large datasets and/or manipulate specific file formats. Therefore, the SPP-Down performs some basic preprocessing before saving the final file.

  • Data preprocessing consists of:
    • .nc4 conversion to .tif;
    • transpose and flip ('y' direction) the raster (.tif) file to correct its orientation;
    • optionally adds a buffer to the shapefile (to cover more pixels along the border); and,
    • crop/mask raster files using the shapefile.

Note: If the desired time resolution is Monthly, the original unit is in mm/hr and will be converted to mm/month considering the correct number of days within each month.

Be careful when comparing the sum of daily to monthly products. According to the Expert Developer Guidance (Dr. George J. Huffman - NASA) on the Algorithm and Processing:
"Limits are imposed on the scaling to avoid unphysical results, so particularly in low-rain areas, the 3B42 values in a month may not sum exactly to the corresponding 3B43. For this reason, 3B43 is the preferred dataset for monthly values."
-- 3B42 and 3B43 refers to daily and monthly products of the Tropical Rainfall Measuring Mission.

Release history

How to use

Create Earthdata account
Link GES DISC with your account

With R

Install the required packages and run the SPP-Down app

if(!require(pacman)) install.packages('pacman')
pacman::p_load(dplyr, raster, rgdal, ncdf4, shiny, rasterVis, viridis, latticeExtra,
               sp, lubridate, rgeos, shinyjs, shinyFiles, rvest, update = F)
               
runGitHub("SPP-Down", "daniel-althoff")

  • Fill all required information
    • Provide your Earthdata account and password
    • Choose desired precipitation product (GPM or TRMM)
    • Choose desired temporal resolution (Daily or Monthly)
    • Set desired data range
    • Select your shapefile (remeber to select all components, i.e, .shp, shx, .dbf, .prj, etc...)
    • Input buffer (>= 0)
    • Select output folder
    • Check if output folder is correct

After the shapefile upload completes, the main panel will render a plot showing the your original shapefile, the buffer, and the average annual precipitation (mm/year) from 1998 to 2017 (20 years).
For this tutorial, we used the Cerrado biome (Brazil) shapefile as an example.

The download button appears once all required information are filled.

Ready? Start download! and check your output directory for a new folder ("SPP_folder") and if data is being downloaded inside it.

Files will be saved as SPP_YYYYMMDD.tif (Daily) or SPP_YYYYMM.tif (Monthly), e.g., TRMM data referring to 01-june-1998: TRMM_19980601.tif (Daily) or TRMM_199806.tif (Monthly).

Enjoy!

😄

Acknowledgements

Special thanks to the Goddard Space Flight Center, Goddard Earth Sciences Data and Information Services Center and NASA's Earth Science Data Systems program.

Data citation and references

  • Althoff, D. (2019), Satellite Precipitation Products Download, GitHub repository, https://github.com/daniel-althoff/SPP-Down
  • Huffman, G.J. (1997), Estimates of Root-Mean-Square Random Error for Finite Samples of Estimated Precipitation, J. Appl. Meteor, https://doi.org/10.1175/1520-0450(1997)036<1191:EORMSR>2.0.CO;2
  • Huffman, G.J., R.F. Adler, D.T. Bolvin, G. Gu, E.J. Nelkin, K.P. Bowman, Y. Hong, E.F. Stocker, D.B. Wolff (2007), The TRMM Multi-satellite Precipitation Analysis: Quasi- Global, Multi-Year, Combined-Sensor Precipitation Estimates at Fine Scale., J. Hydrometeor, https://doi.org/10.1175/JHM560.1
  • Huffman, G.J., R.F. Adler, D.T. Bolvin, E.J. Nelkin (2010), The TRMM Multi-satellite Precipitation Analysis (TMPA). Chapter 1 in Satellite Rainfall Applications for Surface Hydrology, https://doi.org/10.1007/978-90-481-2915-7
  • Tropical Rainfall Measuring Mission (TRMM) (2011), TRMM (TMPA/3B43) Precipitation Estimate L3 1 month 0.25 degree x 0.25 degree V7, Greenbelt, MD, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed: [Data Access Date], https://doi.org/10.5067/TRMM/TMPA/MONTH/7
  • Tropical Rainfall Measuring Mission (TRMM) (2016), TRMM (TMPA/3B42) Precipitation Estimate L3 1 day 0.25 degree x 0.25 degree V7, Edited by Andrey Savtchenko, Goddard Earth Sciences Data and Information Services Center (GES DISC), Accessed: [Data Access Date], https://doi.org/10.5067/TRMM/TMPA/DAY/7