GOLD/SA
A 21-year gridded data set
of near-surface meteorology, surface state variables and fluxes over South
America
GOLD/SA is a spatially and temporally continuous
land-surface data set at 1-degree resolution for the period 1979-1999 over
South America, produced for the Large-Scale Biosphere-Atmosphere Experiment
in Amazonia (LBA). Its intent is to be used for specifying initial
and/or boundary conditions for global climate models, climate variability
analyses over land, and applications in hydrology, ecology or biogeochemistry.
Hybrid sets of forcing data have been produced by combining the 6-hourly
reanalyses with observed monthly data sets to reduce systematic errors
in the reanalysis. These data are then used to drive a land surface
scheme, producing a data set of surface state variables and fluxes.
Land surface model output data are produced as monthly means and instantaneous
pentad grids over the South American domain, and monthly-mean diurnal cycles
are produced over selected grid boxes corresponding to LBA study areas.
GOLD/SA is a special version of the Global
Offline Land-surface Dataset (GOLD) products produced on the Gauussian
grids of the various COLA GCM resolutions. A description of GOLD
can be found in COLA
Technical Report 102.
A manuscript has been prepared that describes
GOLD/SA, and is available
online.
There are five types of data sets,
all on the same 1-degree grid (corresponding to the ISLSCP
Intitative I data):
The data sets will be posted on Beija-Flor
in the near future. They are available currently on the GrADS/DODS
server (GDS) at COLA. The directory listing for the GDS is:
http://monsoondata.org:9090/dods/gold.
Look for GDS data set names listed above. The "info", "dds", and "das"
links provide additional metadata.
To access the data, you need a DODS-enabled
analysis tool (client) such as GrADS version 1.8 or higher. (See the GrADS downloads
page at http://www.iges.org/grads/downloads.html.)
Once you get GrADS running, you can
simply open the data sets with the following commands:
ga-> sdfopen http://monsoondata.org:9090/dods/gold/lba/fixed
ga-> sdfopen http://monsoondata.org:9090/dods/gold/lba/mean
ga-> sdfopen http://monsoondata.org:9090/dods/gold/lba/point
ga-> sdfopen http://monsoondata.org:9090/dods/gold/lba/snap
...etc.
Then you treat the data as you would any
other local data set. An additional benefit of the GDS is that it allows
you to do some analysis on the server side,
which can significantly speed up your interaction with the data. Using
the analysis capabilities of the GDS is
fairly simple if you are already familiar with GrADS syntax. Please consult
the GDS web page for more information about
this: http://www.iges.org/grads/gds.
Look under the headings "How do I access data distributed by the GDS?"
and "How do I do analysis operations on GDS data sets?" The analysis
capability can also be used for accessing
small subsets of the entire data set.
Near Surface Meteorology
There are 8 near surface variables:
| Variable |
Name |
Units |
Source(s) |
| Air temperature (2m AGL) |
air |
K |
NCEP/NCAR reanalysis; Webber and Willmott; CAMS |
| Specific humidity (2m AGL) |
shum |
kg kg-1 |
NCEP/NCAR reanalysis adjusted for consistency with air temperature |
| Wind speed (10m AGL) |
uwnd |
m s-1 |
NCEP/NCAR reanalysis |
| Surface pressure |
pres |
pa |
NCEP/NCAR reanalysis |
| Downward shortwave radiation |
dswrf |
W m-2 |
NCEP/NCAR reanalysis, ISCCP/ISLSCP |
| Downward longwave radiation |
dlwrf |
W m-2 |
NCEP/NCAR reanalysis, ISCCP/ISLSCP |
| Total precipitation |
prate |
kg m-2 s-1 |
NCEP/NCAR reanalysis, Webber and Willmott; CMAP |
| Convective component of precipitation |
cprat |
kg m-2 s-1 |
NCEP/NCAR reanalysis adjusted for consistency with total precipitation |
Land Surface Parameters
These are given once and do not vary in time:
| Variable |
Name |
Units |
Description |
| Vegetation type |
v |
- |
Based on types from ISLSCP I-1 CD-ROM (see Table below) |
| Soil type |
s |
- |
Based on classes from ISLSCP I-1 CD-ROM (see Table
below) |
| Depth of surface soil layer |
d1 |
m |
5 cm globally |
| Depth of root layer |
d2 |
m |
Function of vegetation type, total soil depth |
| Depth of recharge layer |
d3 |
m |
Function of total soil depth from ISLSCP I-1 CD-ROM |
| Wilting point of surface + root layers |
wp1 |
m |
Function of soil type and vegetation type |
| Wilting point of total soil column |
wp2 |
m |
Function of soil type and vegetation type |
| Field capacity of surface + root layers |
fc1 |
m |
Function of soil type |
| Field capacity of total soil column |
fc2 |
m |
Function of soil type |
| Total capacity of surface + root layers |
cap1 |
m |
Function of soil porosity |
| Total capacity of total soil column |
cap2 |
m |
Function of soil porosity |
Vegetation Types
| Type |
Definition |
Seasonal Cycle |
| 1 |
Broadleaf evergreen trees |
No |
| 2 |
Broadleaf deciduous trees |
Yes |
| 3 |
Broadleaf and needle leaf trees |
Yes |
| 4 |
Needle leaf evergreen trees |
Yes |
| 5 |
Needle leaf deciduous trees |
Yes |
| 6 |
Broadleaf trees with groundcover |
Yes |
| 7 |
Groundcover only |
Yes |
| 8 |
Not used |
|
| 9 |
Broadleaf shrubs with bare soil |
Yes |
| 10 |
Broadleaf shrubs with ground cover (Tundra) |
Yes |
| 11 |
Bare soil |
No |
| 12 |
Winter wheat and broadleaf deciduous trees |
Yes |
Soil Texture Types
|
Type
|
Description
|
Porosity
(-)
|
Sat. Matric Potential
(m)
|
Sat. Hydr. Conductivity
(m/s)
|
b Parameter
(-)
|
Comments
|
|
1
|
Coarse
|
0.421
|
0.0363
|
1.41e-5
|
4.26
|
Loamy Sand
|
|
2
|
Medium/Coarse
|
0.434
|
0.1413
|
5.23e-6
|
4.74
|
Sandy Loam
|
|
3
|
Medium
|
0.439
|
0.3548
|
3.38e-6
|
5.25
|
Loam
|
|
4
|
Medium/Fine
|
0.404
|
0.1349
|
4.45e-6
|
6.77
|
Samdy Clay Loam
|
|
5
|
Fine
|
0.465
|
0.2630
|
2.45e-6
|
8.17
|
Clay Loam
|
|
6
|
Ice
|
|
|
|
|
|
|
7
|
Organic
|
0.439
|
0.3548
|
3.38e-6
|
5.25
|
Loam
|
|
0
|
Ocean, Lake
|
|
|
|
|
|
Land Surface - Mean Fields
Reported as monthly means:
| Variable |
Name |
Units |
| Soil moisture in the surface layer |
w1 |
mm |
| Soil moisture in the surface and root layers |
w2 |
mm |
| Soil moisture in the total soil column |
w3 |
mm |
| Soil wetness index of the surface layer |
wi1 |
-- |
| Soil wetness index of the surface and root layers |
wi2 |
-- |
| Surface snow (liquid water equivalent) |
snow |
mm |
| Effective skin temperature |
skin |
K |
| Precipitation rate |
ppl |
mm day-1 |
| Surface runoff rate |
exc |
mm day-1 |
| Total runoff rate |
roff |
mm day-1 |
| Snowmelt rate |
melt |
mm day-1 |
| Transpiration rate |
trnsp |
mm day-1 |
| Bare soil evaporation rate |
sevap |
mm day-1 |
| Direct snow evaporation rate |
snev |
mm day-1 |
| Interception loss |
intrc |
mm day-1 |
| Total evapotranspiration rate |
ett |
mm day-1 |
| Downward shortwave radiation at the surface |
swd |
W m-2 |
| Downward longwave radiation at the surface |
lwd |
W m-2 |
| Upward shortwave radiation at the surface |
swu |
W m-2 |
| Upward longwave radiation at the surface |
lwu |
W m-2 |
| Sensible heat flux |
shf |
W m-2 |
| Latent heat flux |
lhf |
W m-2 |
| Ground heat flux |
ghf |
W m-2 |
Land Surface - Instantaneous
Snapshots
Reported 6 times per month, at 0000UTC on
the 1st, 6th, 11th, 16th, 21st, and 26th.:
| Variable |
Name |
Units |
| Soil moisture in the surface layer |
sm1 |
mm |
| Soil moisture in the surface and root layers |
sm2 |
mm |
| Soil moisture in the total soil column |
sm3 |
mm |
| Soil wetness in the surface layer |
sw1 |
-- |
| Soil wetness in the surface and root layers |
sw2 |
-- |
| Temperature of vegetation canopy |
tc |
K |
| Effective skin temperature |
tskin |
K |
| Temperature of surface layer |
t1 |
K |
| Temperature of root layer |
t2 |
K |
| Temperature of recharge layer |
t3 |
K |
| Total canopy water storage |
capc |
mm |
| Surface storage (snow) |
capg |
mm |
| Soil wetness in the surface layer |
w1 |
-- |
| Soil wetness in the root layer |
w2 |
-- |
| Soil wetness in the recharge layer |
w3 |
-- |
| Soil wetness index |
swi |
-- |
| Available water in the top meter of soil |
s1m |
mm |
| Normalized available water |
naw |
-- |
Land Surface - Monthly-Mean
Diurnal Cycles
Reported at specific grid points:
Note: x is the hour (UTC),
y
is the grid point index (see Table below), t
is the month:
| Variable |
Name |
Units |
| Canopy temperature |
tc |
K |
| Surface temperature |
tg |
K |
| Soil top layer temperature |
t1 |
K |
| Soil root layer temperature |
t2 |
K |
| Soil recharge layer temperature |
t3 |
K |
| Effective skin temperature |
skin |
K |
| Downward shortwave radiation at the surface |
swd |
W m-2 |
| Downward longwave radiation at the surface |
swu |
W m-2 |
| Upward shortwave radiation at the surface |
lwd |
W m-2 |
| Upward longwave radiation at the surface |
lwu |
W m-2 |
| Sensible heat flux |
shf |
W m-2 |
| Latent heat flux |
lhf |
W m-2 |
| Ground heat flux |
ghf |
W m-2 |
| Dry canopy resistance |
rcc |
s m-1 |
| Aerodynamic resistance |
raa |
s m-1 |
Grid Box Locations
Center points of grid boxes are given. All locations are in Brazil
unless indicated otherwise.
|
Site |
Grid box latitude |
Grid box longitude |
| 1 |
Yapu, Columbia |
0.5S |
70.5W |
| 2 |
São Gabriel da Cachoeira |
0.5S |
67.5W |
| 3 |
Manaus |
2.5S |
60.5W |
| 4 |
Santarém |
2.5S |
54.5W |
| 5 |
Almeirim |
1.5S |
52.5W |
| 6 |
Altamira |
3.5S |
52.5W |
| 7 |
Belém |
1.5S |
48.5W |
| 8 |
Marabá |
5.5S |
49.5W |
| 9 |
Fortaleza |
4.5S |
38.5W |
| 10 |
Natal |
5.5S |
35.5W |
| 11 |
Rio Branco |
15.5S |
58.5W |
| 12 |
Ji-Paraná |
10.5S |
61.5W |
| 13 |
Mato Grosso |
11.5S |
55.5W |
| 14 |
Santana do Araguaia |
9.5S |
50.5W |
| 15 |
Brasilia |
15.5S |
47.5W |
| 16 |
São Paulo |
23.5S |
46.5W |
Based on the LBA
Ecology Study Areas.
COLA
4041 Powder Mill Road, Suite 302
Calverton, MD 20705-3106
USA
+1-301-595-7000
Fax +1-301-595-9793