APHRODITE-2 V1101_EX products
1.Introduction
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 its 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 V1101_EX. This means
version 1101 extend.
The interpolation algorithm of V1101 and V1101_EX 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 V1101_EX for 2007-2015, which means, the year 2007 is overlapped
in V1101 and V1101_EX. 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. (netCDF file is not ready). 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 V1101_EX,
so when you publish a paper by using this data, please refer Yatagai et al. (2012, BAMS) and write V1101_EX 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
APHRO_XX_YYYdeg_V1101.ZZZZ
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,
pp183-192.