Readme document for APHRO_JP_V1207@update
24 July 2017
1. Introduction
APHRO_JP is
a gridded (0.05x0.05 degree) surface precipitation data over the land in Japan.
As Kamiguchi et al. (2010, 2011) described, we released daily grid precipitation
data and extreme precipitation indices till 2011 (see http://www.chikyu.ac.jp/precip/data/AphroJP_V1207_readme.txt). It was one of the outcomes by the research project titled
Asian Precipitation - Highly-Resolved Observational Data Integration Towards Evaluation
of Water Resources (APHRODITE). We could launch APHRODITE-2 project during
2016-2019 (http://www.st.hirosaki-u.ac.jp/~aphrodite2/).
As a first
batch of products of APHRODITE-2, we release update of APHRO_JP. We used the
same algorithm to make a 0.05 degree daily precipitation with that of above
mentioned product. However there are two differences of the current set of
products (2009 – 2015) from that of previously released ones; namely
1) We do not contain extreme indices, and
2) We release two different g24-hr accumulation timeh products.
2. Abstract of each data
2.1 Daily precipitation of Japanese local time (AphroJP_JST_DPREC).
AphroJP_JST_DPREC
takes the same g24-hrh accumulation time with that of the previous products
(Kamiguchi et al.,2010).The daily station precipitation data are extracted from
Automated Meteorological Data Acquisition System (AMeDAS)
network observed by the Japan Meteorological Agency
(JMA) and spatial interpolation method is developed by Meteorological Research Institute
(MRI).
Owing to the interpolation method considering of
precipitation climatology and topographical effect.Details of data processing
and characteristics are explained in the paper by Kamiguchi et al. (2010).
Japanese
local time is GMT+9, that means, we are 9 hrs ahead of the universal time. So, a
Japanese day starts from 15 UTC of the previous day and ends at 15 UTC of the
stamped date. Hence, we define as
Start of the
Day (SOD) = -9, and
End of the
Day (EOD) = 15,
Since the 24 hour accumulation of this product is taken
as Japanese local time.
2.2 Daily precipitation data of Universal Time (AphroJP_UTC_DPREC).
To make this version, we extracted hourly precipitation
data from the AMeDAS network observed by JMA. Then we summed up them from 9 JST (= 00
UTC) of the day to 9 JST of next day (= 24 UTC of the day = 00 UTC of next
day). So the 24-hr accumulation time of the daily precipitation of this product
is as follows.
Start of the Day (SOD) = 0, and
End of the Day (EOD) = 24, according to the gstampedh
date.
This 24-hr slot is the same with that of Radar AMeDAS
daily precipitation (RAP) which is another widely used product from JMA.
3. Specification
3.1 Name of the files
As
described above, we released two kinds of data for 2009-2015. The Japanese
24-hr accumulation files are named as Aphro_JST_DPREC.YYYY (YYYY means year in 4-digits), and
The universal time 24-hr accumulation files are named as
Aphro_UTC_DPREC.YYYY
(YYYY means year in 4-digits).
We attached control file of handling these files with
GrADS software.
(AphroJP_JST_DPREC.ctl
and AphroJP_UTC_DPREC.ctl). All
these files are gipped.
3.2 Parameters
Each
data file contains three parameters, namely,
1) Daily precipitation (-99.9 for missing, over ocean)
2) Number of stations used in each 0.05 degree grid box
(whether 1, 2, or -99.9).
3) End of the Day (EOD)
(If
there is a station data, then the value is 15 for JST version, and 24 for UTC
version).
For GrADS users, the control files are below.
[AphroJP_JST_DPREC.ctl]
DSET
^AphroJP_JST_DPREC.%y4
UNDEF -99.9
OPTIONS little_endian template
TITLE APHRO_JP
V1207 daily precipitation
XDEF
460 LINEAR 123.025 0.05
YDEF
440 LINEAR 24.025 0.05
ZDEF
01 LEVELS 1
TDEF 42000
LINEAR 01JAN2009 1dy
VARS 3
precip 1 00 daily
precipitation (mm/day)
nobs 1 00
Number of stations in each grid [1 or 2]
eod
1 00 End of the day (UTC) = 15 UTC
ENDVARS
[AphroJP_UTC_DPREC.ctl]
DSET
^AphroJP_UTC_DPREC.%y4
UNDEF -99.9
OPTIONS little_endian template
TITLE APHRO_JP
V1207 daily precipitation
XDEF
460 LINEAR 123.025 0.05
YDEF
440 LINEAR 24.025 0.05
ZDEF
01 LEVELS 1
TDEF 42000 LINEAR 01JAN2009 1dy
VARS 3
precip 1 00 Daily
precipitation (mm/day)
nobs 1 00
Number of stations in each grid [1 or 2]
eod
1 00 End of the day (UTC) = 24 UTC
ENDVARS
3.3 Area and
horizontal resolution
The data area
is rectangle (lat. 123.0E-146.0E; lon. 24.0N-46.0N) surrounding Japan with
0.05x0.05 degree grid (approx. 5x5 km) in Cartesian coordinate. The number of
horizontal grid is 460/440 in lon/lat, respectively. Available value is
assigned in the land grid except some small islands.
3.4 File structure of one day/one parameter
Value in each
grid is stored with 4-byte real binary of little endian order. No record length
headers are embedded. FORTRAN user can read the file by "direct
access". The file consists of 4-dimensions: time, variable, latitude and
longitude, and the sequence goes in the following order starting from the
fastest varying dimension to the slowest varying dimension: longitude,
latitude, variable, and time. The order of longitude is from west to east and
that of latitude is from south to north.
The order of horizontal plane
(123.0E, 46.0N)
N
(146.0E, 46.0N)
-----------------------------------
|...........................|193200|
-----------------------------------
|. .
|
|. .
|
W
----------------------------------- E
|921|922|..........................|
-----------------------------------
|461|462|......................|920|
-----------------------------------
| 1
| 2 | 3 | 4 |..............|460|
-----------------------------------
(123.0E, 24.0N)
S
(146.0E, 24.0N)
The first
grid (centered at 123.025E, 24.025N) is located on the left-bottom corner and
the second grid is located on the east of the first one. As shown in the above
figure, 460th grid is located at the east end of the line and the 461st grid
moves to the north of westernmost grid.
4. Acknowledgment
We thank Mr.Kenji
Kamiguchi and Mr. Osamu Arakawa who permits to use APHRO_JP program.
5. Contact information
If you have any inquiries, please contact the following
by email.
Dr.
Akiyo Yatagai
Global
Environment and Disaster Prevention Sciences
Faculty/Graduate School of Science
and Technology,
Hirosaki University
URL:
http://www.st.hirosaki-u.ac.jp/~yatagai/
Tel: +81-172-39-3685 Fax: +81-172-39-3543
Email:
APHRODITE-2 project technical team
aphrodite.precinfogathgmail.com (change
gath to @)
6. References
So far,
please refer the following paper. We will inform registered users when the
reference paper of the current version is ready.
Kamiguchi, K., O. Arakawa, A. Kitoh, A. Yatagai, A. Hamada, and N.
Yasutomi, 2010: Development of APHRO_JP, the first Japanese high-resolution
daily precipitation product for more than 100 years, Hydrological Research
Letters, 4, 60-64, doi:10.3178/HRL.4.60.