Summer 2020

Table of Contents: TCC News No. 61
Climate Characteristics of Record-heavy Rain and Record-low Sunshine Durations in Japan in July 2020............................................................................................................................................................................. 1
TCC’s forecasting gridded dataset FAQ ........................................................................................................... 3

Climate Characteristics of Record-heavy Rain and Record-low Sunshine
Durations in Japan in July 2020
TCC issued a press release regarding climate characteristics of Record-heavy Rain and Record-low Sunshine Durationsin Japan in July 2020. An abstract of the press release and the download link for the full article are as follows.
In July 2020, western to northeastern Japan experienced record-heavy rain and record-low sunshine durations.

The month was characterized by a remarkable series of heavy rainfall events from western to eastern Japan from
3rd to 31st July. In some areas, monthly precipitation totals exceeded 2 to 2.4 times the climatological normal,
making the period the wettest since 1946 when records began.

These phenomena are attributed to a continued tendency for large amounts of water vapor to concentratearound western and eastern Japan from two major flows – one from the west along the Meiyu-Baiu front, which
stagnated along mainland Japan due to delayed northward migration of the subtropical jet stream, and the otherfrom the south along the periphery of the North Pacific Subtropical High, which extended southwestward of its
climatological extent.

A persistent upper-level trough over the Yellow Sea also caused an intensification of Meiyu-Baiu front activity
with enhanced vertical upward flow over western and eastern Japan, resulting in prolonged heavy rain.

The delayed northward migration of the subtropical jet stream and the southwestward expansion of the North
Pacific Subtropical High may be attributable to higher-than-normal sea surface temperatures (SSTs) in the Indian
Ocean and related inactivity of the Asian summer monsoon.

URL: https://ds.data.jma.go.jp/tcc/tcc/news/press_20200916.pdf

TCC News1

No.61 | Summer 2020

Figure 1-1. Maximum 48-hour precipitation Figure 1-2. Mean temperature anomalies,amounts (3rd to 31st July, 2020)

precipitation ratios and sunshine duration
ratios for July 2020.
The base line period for the normal is 1981 –2010

Figure 1-3. Atmospheric circulation conditions associated with the climate extremes observed inJuly 2020
(OIKAWA Yoshinori and MOCHIZUKI Yasushi, Tokyo Climate Center)<<Table of contents <Top of this article

TCC News

2

No.61 | Summer 2020

TCC’s forecasting gridded dataset FAQ
As part of the Japan Meteorological Agency’s WMO World Meteorological Centre (WMC) duties, JMA operates
ensemble prediction systems based on an atmospheric global circulation model (AGCM) for one-month prediction
and an atmosphere-ocean coupled global circulation model (CGCM) for prediction covering periods up to six months.
These are available online via the Tokyo Climate Center (TCC) website. This article provides answers to frequently
asked questions TCC receives regarding these forecasting gridded datasets from National Met Service experts andothers, such as information on elements highlighted, initial dates and automatic dataset downloading.
*Note: Access to products on the TCC website is exclusive to National Meteorological and Hydrological Services.
EligiblepartiesshouldaccesstheTCC
requestpageathttps://ds.data.jma.go.jp/tcc/tcc/products/model/Application.html.

Information provided
As of September 2020, TCC provides the following forecasting gridded datasets at
https://ds.data.jma.go.jp/tcc/tcc/gpv/index.html:
One-month forecastHorizontal resolutions: 1.25 and 2.5 degrees

As provision of lower-resolution 2.5-degree data will be terminated by 2021 or thereafter, TCC
recommends the use of 1.25-degree data.

Ensemble statistics1 (ensemble mean values and its anomaly from model climatology) [link]Ensemble size: 50Update frequency: every ThursdayInitial day: 00 UTC of every WednesdayForecast time: second day from the initial day and up to 32 days ahead

Format: GRIB2



Elements:Name of the elements

Levels (hPa)Sea level pressure*1 and the anomaly [Pa]-Daily mean precipitation and the anomaly [mm day-1]-Day field: 00 UTC-00 UTC
Temperature*1 and the anomaly [K]Surface, 850, 700

Relative Humidity [%]850

Geo-potential height*1 and the anomaly [m]500, 100

Wind (u, v) [m s-1]

850, 200

Stream function and the anomaly [m2 s-1]

850, 200

Velocity potential and the anomaly [m2 s-1]

200

*Climatology was calculated from hindcast experiment (1981-2010).

1Shown as “Statistics” on the index page.

TCC News

3No.61 | Summer 2020

*1 The geo-potential height, sea level pressure and temperature are calibrated by subtracting
systematic error from direct model output.


Dataset files are provided per element.

Individual ensemble members [link]
Ensemble size: 50Update frequency: every ThursdayInitial days: 00 and 12 UTC of every Tuesday and WednesdayForecast time: from the base time and up to 33 days aheadFormat: GRIB2



Elements:
Name of the elementsLevels (hPa)Sea level pressure*1 [Pa]-Daily mean precipitation [mm day-1]-Day field: 00 UTC-00 UTC
Temperature*1 [K]Surface, 1000, 850, 700, 500, 300, 200, 100

Relative Humidity [%]1000, 850, 700, 500, 300

Geo-potential height*1 [m]1000, 850, 700, 500, 300, 200, 100

Wind (u, v) [m s-1]

1000, 850, 700, 500, 300, 200, 100

Stream function [m2 s-1]

850, 200

Velocity potential [m2 s-1]

200

*1 The geopotential height, sea level pressure and temperature are calibrated by subtracting
systematic error from direct model output.


Dataset files are provided per element.

Datasets of systematic error [link]Initial days: every 15th and days of the end of the months

Format: GrADS (the binary data filled with 4-byte real numbers)Elements:
Name of the elementsLevels (hPa)Sea level pressure*1 [Pa]-*1Temperature [K]Surface, 1000, 850, 700, 500, 300, 200, 100

Geo-potential height*1 [m]1000, 850, 700, 500, 300, 200, 100

Hindcast (reforecast) dataset [link]
Ensemble size: 13Hindcast periods: Jan 1981 to Dec 2019



Initial days: every 15th and days of the end of the month

Format: GRIB2



Elements:
Name of the elements

TCC NewsLevels (hPa)*1

Sea level pressure [Pa]-Daily mean precipitation [mm day-1]

4

No.61 | Summer 2020

Day field: 00 UTC-00 UTC

Temperature*1 [K]Surface, 1000, 850, 700, 500, 300, 200, 100

Relative Humidity [%]1000, 850, 700, 500, 300

Geo-potential height*1 [m]1000, 850, 700, 500, 300, 200, 100

Wind (u, v) [m s-1]

1000, 850, 700, 500, 300, 200, 100

Stream function [m2 s-1]

850, 200

Velocity potential [m2 s-1]

200

Six-month forecast

Since September 2020, TCC has provided three-month, warm-/cold-season and six-month predictionseasonal forecasting datasets. However, the Center plans to migrate to only six-month forecast data andterminate provision of three-month and warm-/cold-season prediction datasets by the end of 2021.
Accordingly, the use of six-month forecast data is advised.

Ensemble statistics2 (ensemble mean values, anomaly from model climatology and its standard deviation)[link]


Ensemble size: 51

Horizontal resolution: 2.5 degreeUpdate frequency: every 5 days

13 members are calculated every 5 days. Ensemble statistics calculated from latest 51 members.

Forecast period: next month to up to 6 months

Format: GRIB2

Duration of ensemble mean: one-month mean and three-month meanElements:
Name of the elements

Levels (hPa)*1

Sea level pressure [Pa]-Daily mean precipitation [mm day-1]-Day field: 00 UTC-00 UTC

2Temperature*1 [K]Surface, 850

Geo-potential height*1 [m]500Wind (u, v) [m s-1]

850, 200

Stream function [m2 s-1]

850, 200

Sea surface temperature [K]-Dataset files are provided per element.

Individual ensemble members [link]
Ensemble size: 13

Horizontal resolution: 2.5 degreeUpdate frequency: every 5 daysForecast period: next month to up to 6 months

Shown as “Statistics” on the index page.

TCC News

5No.61 | Summer 2020

Format: GRIB2



Relationship between individual ensemble members (described here) and ensemble statistics
calculated 51 members (described above) are depicted in the following figure.

Figure 2-1. Schematic figure of ensemble configurations of operational suite.
Elements:
Name of the elementsLevels (hPa)*1

Sea level pressure [Pa]-Daily mean precipitation [mm day-1]-Day field: 00 UTC-00 UTC

Temperature*1 [K]Surface, 850, 500, 200

Geo-potential height*1 [m]1000, 850, 500, 300, 200, 100

Wind (u, v) [m s-1]

850, 500, 200

Relative Humidity [%]850

Stream function [m2 s-1]

850, 500, 200

Sea surface temperature [K]-Dataset files are provided per element.

Datasets of systematic error [link]Initial days: every 5 daysFormat: GrADS (binary data filled with 4-byte real numbers)Elements:
Name of the elements

Levels (hPa)*1

Sea level pressure [Pa]-Temperature*1 [K]Surface, 850, 500, 200*1TCC News

Geo-potential height [m]850, 500, 300, 200, 100

Sea surface temperature-6

No.61 | Summer 2020

Hindcast (reforecast) dataset

Ensemble size:

Hindcast periods: Jan 1981 to Dec 2019



Initial days: every 15th and days of the end of the month

Format: GRIB2



Elements:
Name of the elements

Levels (hPa)Sea level pressure*1 [Pa]-Temperature*1 [K]Surface, 850, 500, 200

Geo-potential height*1 [m]850, 500, 300, 200, 100

Sea surface temperature-Daily mean precipitation [mm day-1]-Day field: 00 UTC-00 UTCWind (u, v) [m s-1]

850, 500, 200

Specific Humidity [kg kg-1]

850

Relative Humidity [%]Corresponding table between lead time (month) and initial date

Figure 2-2. Corresponding table between leadtime (month) and initial datePost-download data viewing
TCC provides prediction datasets in GRIB2 and GrADS (the binary data filled with 4-byte real numbers) formats.
GRIB2 datasets can generally be decompressed using the “wgrib2” command and viewed via GrADS. For more details
on download, installation and command application, see the brief instructions on the TCC webpage athttps://ds.data.jma.go.jp/tcc/tcc/products/model/tips/QandA.html (password protected).

Automatic data downloads
The Linux “wget” command can be used to download data automatically. For instance, the following command line
enables download of daily ensemble statistics on one-month forecast data for 100-hPa geopotential height anomaly
with a 1.25-degree resolution:

TCC News7No.61 | Summer 2020

wget--no-check-certificate--http-user="USERNAME"--http-passwd="PASSWORD"

https://ds.data.jma.go.jp/tcc/tcc/gpv/model/1mE.Grib2/GPV_1DAY_125/20200715/JMAGEPS_1p25deg_20200715_p
100_Pahh_fcst_em.grb2

Here, USERNAME and PASSWORD are as provided by TCC after registration. Combining this command line with ascheduler such as “cron” will allow automatic download of TCC gridded datasets. IT staff within user organizations
should be able to provide support for this. IDs and passwords should be stored with appropriate security.

Links
Outline of the operational Ensemble Prediction Systems for one-month and seasonal prediction
https://ds.data.jma.go.jp/tcc/tcc/products/model/outline/index.html
Description of JMA's Global Ensemble Prediction System for one-month prediction
https://ds.data.jma.go.jp/tcc/tcc/products/model/outline/extended.html
Description of JMA's Seasonal Ensemble Prediction System (JMA/MRI-CPS2)
http://ds.data.jma.go.jp/tcc/tcc/products/model/outline/cps2_description.html
Application for Long-range Forecast Products from WMC Tokyo
http://ds.data.jma.go.jp/tcc/tcc/products/model/Application.html(MOCHIZUKI Yasushi, Tokyo Climate Center)<<Table of contents <Top of this article

You can also find the latest newsletter from Japan International Cooperation Agency (JICA).
JICA’s World (July 2020)
https://www.jica.go.jp/english/publications/j-world/2007.html
JICA’s World is the quarterly magazine published by JICA. It introduces various cooperation projects and partners
along with the featured theme. The latest issue features “Ensuring Basic Human Rights: A World in Which Everyone
Can Shine”.
Any comments or inquiry on this newsletter and/orthe TCC website would be much appreciated.
Please e-mail to tcc@met.kishou.go.jp.
(Editors: Mochizuki Yasushi
and Tsuji Kazuaki)

Tokyo Climate Center, Japan Meteorological Agency

TCC News8

TCC Website:
https://ds.data.jma.go.jp/tcc/tcc/index.html

No.61 | Summer 2020