APHRODITE-2  V1101EX_R1@@@@@@@@@

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@Last update October 5, 2018



Since the release of APHRODITE V1101 products (Yatagai et al.,2012), APHRODITE daily grid precipitation data sets are widely used. However, except for APHRO_JP (product for Japan), no update has not been made. The product ended in 2007, and update is really expected for diagnosing climate variability and related hydrological studies.

  On the other hand, by getting funding for FY2016-2018, APHRODITE-2 project has started, and one of the main targets is to improve APHRODITE for evaluation of extreme precipitation. Now we can release the new product V1801 for Monsoon Asia; however, to make V1801 product takes time for quality control and judging end of the day (24-hr accumulation time). So, according to requirements from the science community, which is to release update APHRODITE product even it is created with the same algorithm (V1101), we decided to release it as follows, with named V1101EX (This means version 1101 extend). Immediately after the release of V1101EX, we found some problems over India and Taiwan and we have already fixed them. We replaced V1101EX_R1 for V1101EX.

  The interpolation algorithm of V1101 and V1101EX_R1 is the same, but using data policy is slightly changed, since our continuous efforts of quality control (QC) flagged some data.    


2. General Information

2.1 Product

  We make V1101EX_R1 for 2007-2015, which means, the year 2007 is overlapped in V1101 and V1101EX_R1. This is for the users of careful treatment of using the two datasets. Data of Monsoon Asia (APHRO_MA) in simple binary format that can be handled with GrADS software is released now. Those for Middle East (APHRO_ME), Russia (APHRO_RU) and whole Asia (APHRO_PR) will be released in a couple of months.

 Each domain of the product, resolution, file format are the same with what we have released. So, please see the "readme" of V1101 which is attached below.


3. Reference and contact


We have not written a document for V1101EX_R1, so when you publish a paper by using this data, please refer Yatagai et al. (2012, BAMS) and write V1101EX_R1 is update of V1101 and refer this page (http://aphrodite.st.hirosaki-u.ac.jp).


We welcome your feedback. The contact postal address and email addresses are given here.

PI of the APHRODITE-2 project

Prof. Akiyo YATAGAI  (Course of Meteorology, Graduate School of Science and Technology, Hirosaki University)

3 Bunkyocho, Hirosaki City, Aomori, 036-8561, Japan


Technical Inquiries

APHRODITE project team    Aphrodite.precinfo@gmail.com


General Inquiries

APHRODITE secretariat     Aphrodite.secretary@gmail.com





   README document for APHRO_V1101

                                           (Last updated 27 September, 2018)



1.  Introduction


   A suite of precipitation products is being constructed by the Asian

Precipitation -- Highly-Resolved Observational Data Integration Towards

Evaluation of the Water Resources (APHRODITE's water resources) project

in collaboration with the Research Institute for Humanity and Nature and

the Meteorological Research Institute of the Japan Meteorological Agency.


   After releasing our last product, APHRO_V1003R1, in July 2010, we have

made continuous efforts to collect more data and improve quality control

and analysis method.  We now release APHRO_V1101, which includes more

rain-gauge data and data region is changed for the Middle East product

according to the distribution of input gauge data.


   This README interprets the structure of APHRO_V1101 data files

(sections 2-5), explains changes from the previous versions (section 6),

and gives relevant references (section 7).



2.  General Information


2.1  Products


   The products we release are 0.5x0.5-degree and 0.25x0.25-degree gridded

data over Monsoon Asia (APHRO_MA_V1101), the Middle East (APHRO_ME_V1101),

and Russia/Northern Eurasia (APHRO_RU_V1101).


   The gridded fields of daily precipitation are defined by interpolating

rain-gauge observations obtained from meteorological and hydrological

stations throughout the region.  We use new daily precipitation climatology

and interpolate the ratio of the daily precipitation to the climatology at

a resolution of 0.05 degrees, then multiplied each gridded ratio by each

gridded climatology value day-by-day.  We then re-gridded the 0.05-degree

analysis to both 0.5-degree and 0.25-degree grids.  Details are given in a

paper by Yatagai et al. (2009, 2012) and other related papers listed in section 7.


   An indicator is introduced to represent the reliability of the

interpolated daily precipitation fields.  This indicator, named RSTN, was

calculated for each re-gridded 0.50-degree (0.25-degree) cell, by calculating

the proportion of 0.05-degree cell(s) containing station(s).

   The number of input data differs from year to year. Users, interested

in long-term changes should consider this variable.



2.2  Spatial and Temporal Coverage


   Spatial coverage      :  (MA) 60.0E - 150.0E, 15.0S - 55.0N

                         :  (ME) 20.0E -  65.0E, 15.0N - 45.0N

                         :  (RU) 15.0E - 165.0W, 34.0N - 84.0N

   Spatial resolution    :  0.5 degree and 0.25 degree latitude/longitude

   Temporal coverage     :  January 1, 1951 - December 31, 2007 (57 years)

   Temporal resolution   :  Daily



2.3  Units


   Precipitation :  mm/day

   Ratio of 0.05 grid box containing station(s) :  %



2.4  Missing Code


   Precipitation :  -99.9

   Ratio of 0.05 grid box containing station(s) :  -99.9



3.  Data Files and Their Structure


   The product is stored in one file per year.



3.1  Denotation



      XX   :  Region (MA/ME/RU for Monsoon Asia/Middle East/Russia)

      YYY  :  Resolution (050/025 for 0.5/0.25-degree grid)

      ZZZZ :  The year in 4 digits (e.g. 1951, 1952, ..., 2007)


   For the file in NetCDF format, filename ends with the suffix ".nc."


3.2  Structure of Data Files


   Each file contains daily fields for 365 (366 for leap years) days.

These daily fields are arranged according to the Julian calendar.  Daily

fields (data arrays) contain information on the precipitation amount and

ratio of 0.05-degree cells containing a rain gauge.  In the case of a

0.5-degree grid file, each field consists of a data array with longitude

by latitude dimensions of

   180 x 140 elements for APHRO_MA,

    90 x  60 elements for APHRO_ME,

   360 x 100 elements for APHRO_RU.

In the case of the 0.5-degree APHRO_MA product, the first element is a

cell at the southwest corner centered at [60.25E, 14.75S], the second

is a cell at [60.75E, 14.75S], ..., the 180th is a cell at [149.75E,

14.75S], and the 181st is a cell at [60.25E, 14.25S].


[Note for plain binary format]

   The data files are written in PLAIN DIRECT ACCESS BINARY.  In each

daily field, the array for precipitation comes first, followed by

information on the rain gauge. Each element (both precipitation and

rain gauge information) is written as a 4-byte floating-point number

in little endian byte order.  Users should swap the byte order to

big endian if necessary.  There are no 'space', 'end of record', or

'end of file' marks in between.  In the case of the 0.5-degree APHRO_MA

product, the size of a file (0.5-degree grid) is

   4 bytes x 180 x 140 x 2 fields x 365 days = 73,584,000 bytes

for a non-leap year, or 73,785,600 bytes for a leap year.



4.  How to handle the dataset


4.1 Sample of GrADS Control Files


   Each data file needs a *.ctl file to be handled by the GrADS software

(http://www.iges.org/grads/).  Control files for APHRO_V1101 are available

in the same directory as for the corresponding gridded data.  After saving

the control file in the same location as the downloaded data, open this file

after the "ga" prompt (e.g., ga-> open APHRO_MA_050deg_V1101.ctl).


4.2  Sample Fortran 90 Program


   A sample program written in Fortran 90 (read_aphro_v1101.f90) is

available in the directory /V1101.  Note that the little-endian byte order is

assumed in this program.


4.3  NetCDF files


   We provide NetCDF files for each year. They are stored in /V1101/nc with suffix

".nc". Matlab, ArcGIS and many applications can handle NetCDF.



5.  References


5.1 How to cite APHRO_V1101


  Should you refer to our product in your paper/presentation, please

cite Yatagai et al. (2012).


   Yatagai, A., K. Kamiguchi, O. Arakawa, A. Hamada, N. Yasutomi and

       A. Kitoh, 2012:  APHRODITE: constracting a long-term daukt gridded  

       precipitation dataset for Asia based on a dense network of rain gauges,

       BAMS, doi:10.1175/BAMS-D-11-00122.1


  Details on quality control method of our product is described in Hamada et al.(2011)


   Hamada, A., O. Arakawa and A. Yatagai, 2011: An automated quality control

       method for daily rain-gauge data. Global Environmental Research, V15N2,