Supplement: Impact of snow depth analysis bugs on the JRA-55 product (detailedversion)

S1. List of files containing variables affected by the bugs
Table S1.1. List of files containing variables affected by the bugs (model grid data)
Category

Time range

Filename

6 hourly

anl_land.YYYYMMDDHH

Monthly mean

anl_land.YYYYMM

Monthly variance
anl_land_var.YYYYMM
Land surface analysis
Daily mean smooth
fieldsclimatologicalanl_land.clim8110.dayMMDD
normalMonthly mean
climatologicalanl_land.clim8110.monMM
normalSnow depth analysis
fields

Daily

anl_snow.YYYYMMDD18

Monthly mean

anl_snow.YYYYMM_18

Monthly variance

anl_snow_var.YYYYMM_18

Daily mean smoothclimatologicalanl_snow.clim8110.dayMMDD
normalMonthly mean
climatologicalanl_snow.clim8110.monMM
normal3 hourly

fcst_land.YYYYMMDDHH

Monthly mean

fcst_land.YYYYMM

Monthly variance
fcst_land_var.YYYYMM
Land surface forecast
Daily mean smooth
fieldsclimatological
fcst_land.clim8110.dayMMDD
normalMonthly mean
climatological
fcst_land.clim8110.monMM
normalWater equivalent ofaccumulated snow
depth

Snow depth

Water equivalent ofaccumulated snow
depth
Snow depth

Clear sky upward solar
radiation flux(surface)Monthly mean
fcst_phy2m.YYYYMM
Upward solar radiation
flux (surface)Monthly variance
fcst_phy2m_var.YYYYMM
Clear sky upward solar
Daily mean smoothradiation flux
climatological
fcst_phy2m.clim8110.dayMMDD(nominal top of
normalatmosphere)
Upward solar radiation
Monthly mean
flux (nominal top ofclimatological
fcst_phy2m.clim8110.monMM
atmosphere)
normalSensible heat flux3 hourly

Two-dimensional
average diagnostic
fieldsField parameter

fcst_phy2m.YYYYMMDDHH1Table S1.2. List of files containing variables affected by the bugs (1.25-degree
latitude/longitude grid data)
Category

Land surface
analysis fields

Time range
6 hourly

anl_land125.YYYYMMDDHH

Monthly mean

anl_land125.YYYYMM

Monthly variance

anl_land125_var.YYYYMM

Daily meansmoothclimatologicalnormalMonthly mean
climatologicalnormalMonthly mean

anl_snow125.YYYYMM_18

Snow depth
anl_snow125.clim8110.dayMMDD

anl_snow125.clim8110.monMM
fcst_land125.YYYYMMDDHH

Monthly mean

fcst_land125.YYYYMM

Monthly variance

fcst_land125_var.YYYYMM

Monthly mean
Monthly variance
Daily meansmoothclimatologicalnormalMonthly mean
climatologicalnormalWater equivalent ofaccumulated snow
depth

anl_snow125_var.YYYYMM_18

3 hourly

Daily meansmoothclimatologicalnormalMonthly mean
climatologicalnormalField parameter

anl_land125.clim8110.monMM
anl_snow125.YYYYMMDD18

3 hourly

Two-dimensional
average diagnostic
fieldsanl_land125.clim8110.dayMMDD

DailyMonthly variance
Snow depth analysis
Daily mean
fieldssmoothclimatologicalnormalMonthly mean
climatologicalnormalLand surface
forecast fields

Filename

fcst_land125.clim8110.dayMMDD

Water equivalent ofaccumulated snow
depth
Snow depth

fcst_land125.clim8110.monMM
Clear sky upward
solar radiation flux
(surface)
fcst_phy2m125.YYYYMM
Upward solar
radiation flux
fcst_phy2m125_var.YYYYMM(surface)
Clear sky upward
solar radiation flux
fcst_phy2m125.clim8110.dayMMDD(nominal top ofatmosphere)
Upward solar
radiation flux
fcst_phy2m125.clim8110.monMM(nominal top ofatmosphere)
Sensible heat flux
fcst_phy2m125.YYYYMMDDHH2

S2. Use of masking data
Masking data (JRA-55_mask_en.zip) are provided to specify grid points affected by
the bugs for each of the symptoms described in JMA’s notice of 18 December 2015. These
are areas and periods with unrealistically deep snow values (Section 1) and grid points
with errors in snow cover climatology interpolation (Section 2). Users are advised tocheck the masking data to determine potential impacts when using the affectedvariables specified in Section S1.
S2.1. Directory structureJRA-55_mask_en_ja.zip contains compressed masking data (ZIP format) with thedirectory structure shown below.
Mask -+- mask1_LL125 -+- mask1_LL125_YYYYMM.dat (1-byte integer data)+- ...
+- mask1_LL125.monthly.ctl+- mask1_TL319 -+- TL319_general.pdef+- mask1_TL319_YYYYMM.dat (1-byte integer data)+- ...
+- mask1_TL319.monthly.ctl+- mask2_LL125 -+- mask2_LL125_MM.dat(1-byte integer data)+- ...
+- mask2_LL125.monthly.ctl+- mask2_TL319 -+- TL319_general.pdef+- mask2_TL319_MM.dat(1-byte integer data)+- ...
+- mask2_TL319.monthly.ctl
YYYY: year, MM: month*.ctl GrADS (see Subsection S2.3) control file*.pdef GrADS definition file for projection
S2.2. Data format
S2.2.1. Masking data for areas and periods with unrealistically deep snow values(1.25-degree latitude/longitude grid data) (mask1_LL125)
 Data type: 1-byte integer
 Values: 1 for grid points with errors and 0 for others File organization:
The first 288 bytes of the files contain data for the 90th parallel north, startingfrom zero degrees longitude (the prime meridian) toward the east at intervalsof 1.25 degrees. The remaining parallels follow at intervals of 1.25 degrees
toward the south.
 File composition:
Monthly files for the period from January 1958 to December 2014 (684 in total)
S2.2.2. Masking data for areas and periods with unrealistically deep snow values (modelgrid data) (mask1_TL319)
 Data type: as per mask1_LL125
 Values: as per mask1_LL125
 File organization:3

The first 48 bytes of the files contain data for the northernmost parallel,
starting from zero degrees longitude (the prime meridian) toward the east. The
remaining parallels follow toward the south. The number of grid points in eachparallel varies with latitude. For details of the latitude and the number of grid
points in each parallel of the model grid, see the JRA-55 product users’
handbook(Modelgriddata;
http://jra.kishou.go.jp/JRA-55/index_ja.html#manual).
File composition: as per mask1_LL125

S2.2.3. Masking data for grid points with errors in snow cover climatology interpolation(1.25-degree latitude/longitude grid data) (mask2_LL125)
 Data type: as per mask1_LL125
 Values: as per mask1_LL125
 File organization: as per mask1_LL125
 File composition:
Monthly files from January to December (12 in total)
S2.2.4. Masking data for grid points with errors in snow cover climatology interpolation(model grid data) (mask2_TL319)
 Data type: as per mask1_LL125
 Values: as per mask1_LL125
 File organization: as per mask1_TL319
 File composition: as per mask2_LL125
S2.3. Application program for analysis and visual representation
Additional files (*.ctl, *.pdef) are also included to support handling of masking datawith the Grid Analysis and Display System (GrADS; a free program for analysis andvisual representation of geoscience data). With these files, masking data can bevisualized as outlined below.
Example of visual representation with masking data for areas and periods withunrealistically deep snow values (March 1988) (Fig. S2.1)$ grads(Start up GrADS.)> open “Masking data directory”/mask1_LL125.monthly.ctl(Open the GrADS control file.)> set time Mar1988(Set the time to March 1988.)> set gxout grfill(Select “Filled grid boxes” as the graphics type.)> set rbcols 0 2(Select transparent (0) and red (2).)> set clevs 0.5(Set the threshold to 0.5.)> display mask1(Display masking data.)

Masking data for grid points with errors in snow cover climatology interpolation canbe visualized in the same way as above.
For details of GrADS, see http://cola.gmu.edu/grads/grads.php.

4Fig. S2.1 Visual representation of masking data for areas and periods withunrealistically deep snow values (March 1988)
Areas affected by the bugs are shaded in red. Values are 1 in areas shaded in red and 0
in the rest.

S2.4. Checking for impacts on the variables listed in Section S1
 Snow depth (and water equivalent of accumulated snow depth)
Users are advised to check both the masking data for areas and periods withunrealistically deep snow values and the masking data for grid points with errors insnow cover climatology interpolation.
Upward solar radiation flux
Users are advised to check the masking data for grid points with errors in snow cover
climatology interpolation.
Sensible heat flux
Users are advised to check the masking data for grid points with errors in snow cover
climatology interpolation.
5

S3. Apology and correction regarding errors in JMA’s notice of 18 December
2015
The errors detailed below appeared in the periods and grid points listed in JMA’s
notice of 18 December 2015. JMA apologizes for these issues.
Periods of significant impact
Corrections for the periods listed in Section 1 tables

Area
Subsection 1.2
Western Siberia
Table 1.2, Area 1
Subsection 1.2
Western Siberia
Table 1.2, Area 2
Subsection 1.6
Northern Canada
Table 1.6, Area 1
Subsection 1.8
Northeastern North
America
Table 1.8, Area 1

For

Read

1958/1959 to 1985/1986

1958 to 1985/1986

1966/1967 to 1979/1980, 1987/1988

1958, 1966/1967 to 1979/1980,
1987/1988

1976/1977

1977/1978

1958/1959 to 1990/1991, 1995/1996 to
1998/1999, 2003/2004 to 2005/20061958 to 1990/1991, 1995/1996 to
1998/1999, 2003/2004 to 2005/2006

The same errors also appeared in JRA-55_snow_bugs_list1_en.txt. The corrected
ASCII file (JRA-55_snow_bugs_list1_corr_en.txt) should be used instead.
The corrected ASCII file contains investigation results for the period up to 2014,
whereas the original ASCII file covered the period up to 2012. Results for the period
after 2015 will be released once investigation is complete.
List of grid points where snow depth values were found to be unrealistically low
The list for February in JRA-55_snow_bugs_list2_ja.txt was erroneously replacedwith the list for January. The corrected ASCII file (JRA-55_snow_bugs_list2_corr_ja.txt)
should be used instead.
6