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The Halogen Occultation Experiment (HALOE) is one of 10 instruments
aboard the Upper Atmosphere Research Satellite (UARS). The HALOE instrument
uses solar HALOE uses the principle of satellite solar occultation to sound
the stratosphere, mesosphere, and lower thermosphere. Through this
technique, HALOE measures vertical profiles of atmospheric ozone
(O3), hydrogen chloride (HCl), hydrogen fluoride (HF), methane
(CH4), water vapor (H2O), nitric oxide (NO), nitrogen
dioxide (NO2), aerosol extinction, and temperature. Data
collection began 11 October 1991 and continues to the present. Currently,
HALOE level 3AT version 19 data products are available from the Goddard Space Flight Center (GSFC) Distributed Active
Archive Center (DAAC).
-
-
-
UARS HALOE LEVEL 3AT DAILY TIME ORDERED DATA
-
-
The HALOE level 3AT data are a subset of the UARS dataset. HALOE
level 3AT data are daily time-ordered data, arranged at time
intervals of 65.536 seconds, or about 495 km intervals along the
LOS tangent track. The reference time at which level 3AT data are
arranged is common across all UARS level 3AT files.
-
-
HALOE studies the dynamics of polar and other atmospheric regions
using the tracers, HF, CH4, and H2O. Studying
the trends in HCL and HF will help distinguish the relative
importance of anthropogenic versus natural chlorine sources and
analyze in detail the development and recovery of the Antarctic
ozone hole. Additional studies are intended to identify and assess
stratosphere/troposphere exchange.
-
-
Vertical profiles of O3, HCL, HF, CH4,
H2O, NO, NO2, aerosol extinction, and
temperature versus pressure.
-
-
The HALOE Level 3AT data files are written in the Standard Data
Format Units (SFDU) format. Each file consists of three records
called SFDU, LABEL, and DATA. SFDU and LABEL records contain
descriptive information about the instrument and the data, such as
start/stop time of the data, number of records in the file, etc.
The DATA record contains the profile data and their standard
deviations. Time, latitude longitude, local solar time, and solar
zenith angles are provided with each DATA record. Each data file is
accompanied by a short ASCII metadata file, which provides
descriptive information such as the start and stop time of the
data, file record lengths, and the UARS quality flag.
After the original level 3A file formats were agreed to, it was
realized that additional parameters were needed to describe the MLS
data. Level 3LP and 3TP parameter files were created to include
values for the HALOE diagnostic quantities and retrieval quality
indicators. These are needed to supply reliable interpretation of
the data in the corresponding data files. Each level 3AT file for a
given day is accompanied by a level 3TP file. The 3TP file also
consists of the three record types SFDU, LABEL and DATA, and is
also accompanied by their own ASCII metadata files.
-
- All UARS level 3AL and 3AT files use the same formats to allow
for intercomparisons of atmospheric profiles between the different
instruments. Other UARS instruments which measure chemical species
include the Cryogenic
Limb Array Etalon Spectrometer (CLAES), the Improved
Stratospheric and Mesospheric Sounder (ISAMS), and the Microwave
Limb Spectrometer (MLS).
-
-
- Name:
- James M. Russell III
- Address:
- NASA Langley Research Center
- Mail Stop 401B
- 21 Langley Boulevard
- Hampton, VA 23681-0001
- Telephone Numbers:
- Phone: +1 757 728 68931
- FAX: +1 757 727-5090
- Electronic Mail Address:
- jmr@hamptonu.edu
-
- Halogen Occultation Experiment
-
- HALOE Data Manager:
- Pat Purcell
- Address:
- NASA Langley Research Center
- Mail Stop 402
- Hampton, VA 23681-0001
- Telephone Numbers:
- Phone: +1 757 864-7469
- FAX: +1 757 864-8461
- Electronic Mail Address:
- purcell@hops.larc.nasa.gov
- In a solar occultation experiment such as HALOE, the attenuation of
the sun's radiation by the limb of the atmosphere is measured as the sun
rises and sets relative to the satellite. The attenuated sunlight is
measured in several IR wavebands using wide band and gas cell correlation
radiometry techniques.The UARS orbit has an inclination of 57 degrees and
a period of about 96 minutes. This results in HALOE viewing on average 15
sunrises and 15 sunsets each day. Due to the geometry, sunrise and sunset
events occur separately at roughly constant latitudes each day, that is,
all 15 sunrise events encircle a given latitude spaced about 25 degrees
apart in longitude each day. As the orbit precesses, HALOE sweeps from
80S to 80N in latitude approximately every 30 days.
-
-
-
HALOE is a satellite solar occultation experiment designed to
monitor the vertical distributions of HCl, HF, CH4, and NO by gas
filter correlation radiometry and H2O, NO2, O3, and temperature
versus pressure using CO2 absorption by broadband filter radiometry
(Russell et al., 1993a). Aerosol extinction is directly measured in
each of the gas filter channel wavelengths which range from 2.5 to
5.26 m (Hervig, et al., 1993). The broad band radiometer
measurements range from 2.7 to 10 m wavelength. The absorption of
solar energy at selected spectral bands is used to infer vertical
profiles of atmospheric temperature, pressure, and mixing ratios of
key gases involved in ozone chemistry. The HALOE instrument
includes both broadband and gas filter channels covering the
spectral range from 2.45 to 10.04 microns.
As viewed from UARS, there are typically 15 sunrises and 15
sunsets per day. For each sunrise and sunset event, HALOE
automatically acquires the sun and goes through a series of
operational modes. These modes include balance of the gas filter
correlation channels, limb to limb scans of the solar disk, a
calibration sequence involving viewing the sun through a series of
gas cells and neutral density filters, and finally an atmospheric
track mode.
-
-
Satellite data are collected from a near-circular Earth orbit
of about 585 km altitude and 57 degree inclination.
-
-
Upper
Atmosphere Research Satellite (UARS).
-
- UARS was launched September 12, 1991 with the mission of
investigating the chemical and dynamical processes of the Earth's
upper atmosphere. See the UARS Project
document for more information.
- Data are telemetered from UARS through the Tracking and Data Relay
Satellite System (TDRSS) to the Data Capture Facility (DCF) at NASA GSFC.
From there the data are given an initial quality check, and are then
forwarded to the UARS Central Data
Handling Facility (CDHF). The instrument PI teams are connected to
the CDHF through remote analysis computers (RACs), where they have
developed software to convert the raw data to higher level processed
data. The CDHF uses the production software to convert the level 0 (raw)
data to level 1, 2, 3A and 3B data. The Goddard DAAC acquires the UARS
data from the CDHF.
-
-
-
The HALOE processing produces retrieved profiles of temperature,
pressure, HCl, HF, CH4, NO, NO2, O3, and H2O. In addition, aerosol
extinction profiles are retrieved for each modulation channel
wavelength, 2.45, 3.4, 3.47 and 5.26 microns and the CO2 channel
wavelength of 2.8 microns. Although some improvements are still to
come, current results for all products are suitable for research
use, if quality and error estimates are closely observed.
NOTE: The AEXTCO2 subtype is not available in
version 19.
-
-
-
-
-
Latitudinal coverage is from 80 S to 80 N over the course of a
year and includes extensive observations of the Antarctic
region during spring. The latitude and longitude locations of
the actual retrievals vary with each retrieval point due to
motion of the spacecraft during the length of the occultation
event. For this reason, two HALOE Level 3TP parameter files are
produced, one containing the latitude and one containing the
longitude at each UARS pressure level for each HALOE event.
Also, the Level 3AT data are assigned a latitude/longitude
location corresponding to that of the 30 km retrieval point.
The altitude range of the measurements extends from about 15
km to 60 through 130 km, depending on channel.
-
-
Data coverage for HALOE on 5/23/1992.
-
-
Horizontal resolution is 4 degrees for level 3AL files, and
about 495 km along the orbital track for level 3AT files.
Vertical resolution for level 3A files is about 2.5 km
between pressure surfaces.
-
Projection:
-
Not Applicable.
-
-
All HALOE level 3A data have been referenced to the UARS
standard pressure grid. The index of the data array defines the
pressure level (in millibars) given by:
P(i) = 1000 x 10**(-i/6) mb, where i=0,1,2,...54
-
-
-
Temporal coverage is from 11 October 1991 to 9 November 1997.
Below is a list of dates within the above time period for which
HALOE data are missing or unavailable:
Days Since Launch Date Ranges
----------------- ----------------------------
33 (14-OCT-1991)
35 (16-OCT-1991)
100 to 110 (20-DEC-1991 to 30-DEC-1991)
174 to 179 (03-MAR-1992 to 08-MAR-1992)
211 to 216 (09-APR-1992 to 14-APR-1992)
264 (01-JUN-1992)
266 to 303 (03-JUN-1992 to 10-JUL-1992)
360 (05-SEP-1992)
460 to 472 (14-DEC-1992 to 26-DEC-1992)
477 (31-DEC-1992)
533 to 538 (25-FEB-1993 to 02-MAR-1993)
540 (04-MAR-1993)
641 to 651 (13-JUN-1993 to 23-JUN-1993)
658 (30-JUN-1993)
694 to 697 (05-AUG-1993 to 08-AUG-1993)
716 to 719 (27-AUG-1993 to 30-AUG-1993)
744 (24-SEP-1993)
821 to 831 (10-DEC-1993 to 20-DEC-1993)
895 to 898 (22-FEB-1994 to 25-FEB-1994)
902 (01-MAR-1994)
1001 to 1012 (08-JUN-1994 to 19-JUN-1994)
1077 to 1082 (23-AUG-1994 to 28-AUG-1994)
1181 to 1194 (05-DEC-1994 to 18-DEC-1994)
1252 to 1263 (14-FEB-1995 to 25-FEB-1995)
1316 to 1321 (19-APR-1995 to 24-APR-1995)
1342 to 1349 (15-MAY-1995 to 22-MAY-1995)
1354 (27-MAY-1995)
1362 to 1374 (04-JUN-1995 to 16-JUN-1995)
1388 to 1395 (30-JUN-1995 to 07-JUL-1995)
1418 to 1419 (30-JUL-1995 to 31-JUL-1995)
1435 to 1443 (16-AUG-1995 to 24-AUG-1995)
1450 to 1451 (31-AUG-1995 to 01-SEP-1995)
1495 to 1497 (15-OCT-1995 to 17-OCT-1995)
1527 to 1528 (16-NOV-1995 to 17-NOV-1995)
1541 to 1553 (30-NOV-1995 to 12-DEC-1995)
1568 to 1569 (27-DEC-1995 to 28-DEC-1995)
1605 to 1623 (02-FEB-1996 to 20-FEB-1996)
1674 to 1676 (11-APR-1996 to 13-APR-1996)
1706 to 1709 (13-MAY-1996 to 16-MAY-1996)
1721 to 1734 (28-MAY-1996 to 10-JUN-1996)
1747 to 1749 (23-JUN-1996 to 25-JUN-1996)
1776 to 1784 (22-JUL-1996 to 30-JUL-1996)
1794 to 1808 (09-AUG-1996 to 23-AUG-1996)
1815 to 1820 (30-AUG-1996 to 04-SEP-1996)
1854 to 1860 (08-OCT-1996 to 14-OCT-1996)
1883 to 1891 (06-NOV-1996 to 14-NOV-1996)
1902 to 1914 (25-NOV-1996 to 07-DEC-1996)
1928 to 1932 (21-DEC-1996 to 25-DEC-1996)
1958 to 1959 (20-JAN-1997 to 21-JAN-1997)
1973 to 1984 (04-FEB-1997 to 15-FEB-1997)
1997 to 2000 (28-FEB-1997 to 03-MAR-1997)
2034 to 2039 (06-APR-1997 to 11-APR-1997)
2046 (18-APR-1997)
2062 (04-MAY-1997)
2066 to 2069 (08-MAY-1997 to 11-MAY-1997)
2083 to 2094 (25-MAY-1997 to 05-JUN-1997)
2101 to 2103 (12-JUN-1997 to 14-JUN-1997)
2108 to 2111 (19-JUN-1997 to 22-JUN-1997)
2130 to 2136 (11-JUL-1997 to 17-JUL-1997)
2139 to 2140 (20-JUL-1997 to 21-JUL-1997)
-
- The temporal resolution of HALOE level 3A data granules is
daily.
-
-
-
There are 13 parameters for HALOE level 3AT data products. The
measured parameters are listed below with the original HALOE
subtype name, DAAC parameter name, and units:
Subtype |
DAAC Parameter Name |
Units |
Altitude Range |
HCL |
HYDROGEN CHLORIDE |
vmr |
10-60 km |
HF |
HYDROGEN FLOURIDE |
vmr |
10-60 km |
CH4 |
METHANE |
vmr |
15-75 km |
NO |
NITRIC OXIDE |
vmr |
10-130 km (below 78 km) |
|
|
|
10-20 km (above 78 km) |
O3 |
OZONE |
vmr |
10-85 km |
H2O |
WATER VAPOR |
vmr |
10-75 km |
NO2 |
NITROGEN DIOXIDE |
vmr |
10-55 km |
Temperature |
ATMOSPHERIC TEMPERATURE |
K |
10-130 km |
AEXTCH4 |
AEROSOL EXTINCTION AT 3.46 µm |
km -1 |
10-50 km |
AEXTCO2 |
AEROSOL EXTINCTION AT 2.80 µm |
km -1 |
10-50 km |
AEXTHCL |
AEROSOL EXTINCTION AT 3.40 µm |
km -1 |
10-50 km |
AEXTHF |
AEROSOL EXTINCTION AT 2.45 µm |
km -1 |
10-50 km |
AEXTNO |
AEROSOL EXTINCTION AT 5.26 µm |
km -1 |
10-50 km |
NOTE: volume mixing ratio (vmr) equals
10e-6 ppmv.
NOTE: AEXTCO2 subtype is not available in
version 19)
-
-
Level 3AT data is organized into thirteen files (granules) per day,
one each for temperature, mixing ratios of H2O, NO2, O3, NO, CH4,
HCl, and HF, and aerosol extinction values for CO2, NO, CH4, HCl,
and HF channels. Each file (granule contains the retrievals for the
sunrise and sunset events for the day (typically 29 or 30 total),
and files are organized by event. The two Level 3TP files are
latitude and longitude for each pressure level of each event for
the day.
Each HALOE level 3A granule is a multi-file granule consisting
of six files:
-
The binary data file (files ending with PROD, or *PROD
extension) which contains the vertical profile data, and
quality (standard deviations), along with time, average
latitude and longitude, local solar time, and solar zenith
angle.
-
An ASCII metadata file (files ending with META, or *META
extension) associated with the data file containing items such
as the begin date, end date, PI assigned quality flag and
record length size of the data file.
-
Two binary parameter files (also *PROD extension) designated
3TP for 3AT granules. The subtypes for these files are LAT and
LON. The first contains the latitude values for each individual
pressure level and the second contains the corresponding
longitudes.
- Two ASCII metadata file associated with the parameter files
(also *META extension). The information is identical to the
metadata file associated with the data file, except that the
record length applies to the parameter file.
The naming convention for UARS files distributed by the Goddard
DAAC is as follows:
HALOE_Llll_Sssss_Ddddd
.Vvvvv_Ccc_xxxx,
The format for granule file names is
HALOE_Llll_Sssss_Ddddd
.Vvvvv_Ccc_xxxx, where
- lll
- is the UARS processing level (3AT or 3TP),
- ssss
- is the subtype or parameter,
- dddd
- is the UARS acquisition day (0001 = 12 September 1991),
- vvvv is the data version number,
- cc
- is the data version cycle number, and
- xxxx
- is the file extension (PROD for the binary files, or META for
the ASCII metadata files)
For a full description of the naming convention see the
"meta_desc.doc" file.
Average granule size is about 15 Kb for HALOE_L3AT_DAILY
granules. The *META files are small, only about 730 bytes each.
-
- The data are in a native UARS format. The files were originally
created on a VAX/VMS system at the UARS CDHF, and now exist as UNIX
stream files at the Goddard DAAC. HALOE data file structures are
presented in the Standard Formatted Data Units (SFDU) documents
listed in the References section.
-
-
-
-
- The mixing ratios are interpolated to the UARS standard
pressure array from the Level 2 data file using a first-order
linear interpolation based on ln(pressure). The interpolated
quality indicators are the higher of the surrounding standard
deviation values except for temperature.
-
-
-
The data processing is divided into three main jobs. The first
job reads the raw telemetry files or level 0 data and
interprets the data packet headers. The measurements are
separated according to the atmospheric line observed and saved
in intermediate files. Next the instrument calibration data is
used to subtract dark current and to convert the count rate per
bin to a line of sight intensity given in rayleighs. Once the
known instrument corrections are made effects due to the UARS
spacecraft are determined. The orbit attitude data are used to
compute the location of the tangent point for each line of
sight for each measurement bin. The frequent phase measurements
are also processed in the first job step. The level 1 data,
cataloged at the end of job step 1, contain the calibrated data
and the geo-referencing data. These data are input to job step
2.
The second step uses transmission profiles, difference
signal profiles from the gas filter channels, and solar source
functions from the solar scans to retrieve temperature,
pressure, and mixing ratios of HCl, HF, CH4, H2O, O3, NO, NO2,
aerosol and temperature versus pressure. The retrieval method
incorporates a simple "onion peel" procedure stabilized at the
top and bottom of the profile with a scalar optimal estimation
formulation [Connor and Rodgers, 1989]. The forward model for
the gas filter channels (HF, HCl, CH4, NO) is a rigorous
line-by-line code which is necessary for the effective high
spectral resolution of these channels. All spectral dependence,
including thermal and Doppler shift effects, is explicitly
modeled. Along-path mixing ratio gradients are also included in
the forward model for the diurnally active gases NO, NO2, and
O3.
The final job step uses transmission profiles, difference
signal profiles from the gas filter channels, and solar source
functions from the solar scans to retrieve temperature,
pressure, and mixing ratios of HCl, HF, CH4, H2O, O3, NO, NO2,
aerosol and temperature versus pressure. The retrieval method
incorporates a simple "onion peel" procedure stabilized at the
top and bottom of the profile with a scalar optimal estimation
formulation [Connor and Rodgers, 1989]. The forward model for
the gas filter channels (HF, HCl, CH4, NO) is a rigorous
line-by-line code which is necessary for the effective high
spectral resolution of these channels. All spectral dependence,
including thermal and Doppler shift effects, is explicitly
modeled. Along-path mixing ratio gradients are also included in
the forward model for the diurnally active gases NO, NO2, and
O3.
HALOE Level 3 processing uses one Level 2 daily product file
as input with some exceptions when the first event is in the
previous day's Level 2 file. Each Level 3AT file includes the
complete set of retrievals for the sunrise and sunset events
which begin during that day. The Level 2 profiles are on a
vertical grid. Level 3AT processing produces profiles for these
parameters on the UARS standard pressure grid of
P(i) = 1000.0 * ( 10**(-i/6) ), i = 0,1,...54.
Level 3AT processing consists of one program (L3ATLIN) whose
function is to produce Level 3AT and 3TP product files on the
UARS standard pressure grid from a Level 2 product file.
L3ATLIN processes sequentially through each event
(sunrise/sunset) in a day of Level 2 data and produces separate
files for each of the eight parameters and associated aerosol
data along with one latitude 3TP file and one longitude 3TP
file. The Level 3AT and 3TP files are arranged by event in the
time order of the measurements.
-
- Reprocessing of the data occur about once a year.
-
-
-
- None.
-
- None.
-
-
- The data quality is given by the standard deviation of the
quantity. Each data element in each file is stored along with a
standard deviation which has been calculated by the analysis
software. The nominal error is 10 m/s for the wind and 25 K for
temperature.
-
-
The quality indicator associated with each data point is the
precision of the HALOE measurement in the form of a standard
deviation as calculated in the Level 2 processing. In Level 3AT, if
no value is available for a pressure level, the highest standard
deviation around this 3AT pressure level is taken from the Level 2
data.
-
-
All data are checked by the WINDII science team and assigned
quality values. These values appear as the DATA_QUALITY_UARS
fields in the ASCII metadata files. The format for
DATA_QUALITY_UARS is a 3 character field of the form "p.q"
where:
VALUE MEANING
for p 0 Machine inspected
1 Qualitative evaluation
2 Intensive analysis
for q 1 less than 50% good data
2 50% - 75% good data
3 76% - 98% good data
4 better than 98% good data
-
-
Error estimates in the data set do not include systematic
components. Only noise error and error due to aerosol
correction are estimated and root sum squared. This
underestimates errors where these two mechanisms are not the
dominant error source but is accurate at high altitudes and in
conditions of heavy aerosol for O3, H2O and NO2. For HF, HCl,
CH4, NO and aerosol the total error at low altitudes (below 20
km) is greater than indicated by the recorded error. Systematic
components are reported in the validation papers submitted for
the JGR UARS Special Validation Issue. The high altitude errors
listed in the files accompanying the data can over estimate the
error in conditions of low signal to noise (S/N) by sometimes
as much as a factor of four. This is due to low signal
smoothing and retrieval stability procedures that were not
correctly incorporated in the error estimates. For retrieved
values that are a factor of 2 or more larger than estimated
errors, the estimates are accurate. Much of the improved low
S/N results come at the expense of lower resolution.
-
-
The quality indicator associated with each data point is the
precision of the HALOE measurement in the form of a standard
deviation as calculated in the Level 2 processing. In Level
3AT, if no value is available for a pressure level, the highest
standard deviation around this 3AT pressure level is taken from
the Level 2 data.
-
- Data files are checked to ensure that they are properly
transferred and translated from their original VAX/VMS format at
the UARS CDHF to the DAAC's UNIX format. No additional data
checks are performed by the DAAC.
-
-
The data files exist as UNIX stream files at the DAAC. Binary data
are IEEE formatted. The binary data files should be read on 32 bit
machines running UNIX operating systems. This is especially
important for fields which are IEEE floating point values, such as
the profile data and quality values. If you are going to use a non
32-bit and/or non-UNIX machine, then you will need to write your
own conversion routines to read the data files.
File record length information is only listed in the ASCII
metadata files (*META extension) which accompany the data and
parameter files.
-
-
None at this time.
-
-
Level 3AT data consists of atmospheric profiles on a vertical
spacing corresponding to the standard UARS pressure grid. In many
cases this vertical spacing is much broader than the HALOE Level 2
point spacing. For this reason, HALOE Level 3AT data is not always
representative of the HALOE Level 2 data from which it was
produced. Therefore, care should be taken in interpreting the HALOE
Level 3AT data between the UARS standard pressure levels. Also, the
temperature profiles are retrieved on a 1.5 kilometer grid,
interpolated to a 0.3 kilometer grid, and then interpolated to the
UARS Level 3AT pressure grid. The temperature standard deviation
values, on the other hand, are taken directly from the 1.5
kilometer gridded values. The standard deviation value of -999.0
indicates a temperature value from NMC or climatology.
With the last few points of all HALOE Level 2 profiles being
suspect, large variations may occur at the bottom of the profiles.
On rare occasions the Level 3AT interpolation will wash out these
variations and they will be reduced or not appear at all in the
interpolated 3AT profile. In cases where this occurs, the comment
associated with the quality number will not accurately describe the
bottom of the profiles.
-
- None.
Anticipated uses of these data are in the fields of understanding
unperturbed atmospheric chemistry and dynamics, tracking global change
and long term atmospheric trends, predicting atmospheric response to
chemical or energetic perturbations, environmental and agricultural
planning, weather forecasting, atmospheric energy input and loss studies,
and radiation budgets.
- Future reprocessing of the data are possible.
-
-
-
Simple read/dump programs are available for reading the HALOE level
3A data files. The read programs are available in both Fortran and
C languages. These programs simply print the file contents to the
screen.
The *META and *PROD files (see the Data
Granularity section) must be kept in the same directory,
because the programs require the *META file as the input parameter
in order to read the *PROD file. The *META file is necessary
because it contains file record length information, which is not in
the *PROD files.
If you are using the Fortran READ programs you may need to
change the OPEN statement. Some machines read 4 byte words, while
other machines read 1 byte. If the program isn't working correctly,
you should try changing RECL=RECSIZ/4 to RECL=RECSIZ.
Contact science@eosdata.gsfc.nasa.gov for
problems with the read/dump software.
-
-
To compile the programs, just type:
f77 FILE_NAME.F -o FILE_NAME (Fortran programs)
or cc file_name.c -o file_name (C programs)
Below are examples showing how to run the programs:
$ READUMP_L3AT_DATA (Fortran program)
PLEASE ENTER META DATA FILE NAME BELOW:
HALOE_L3AT_SH2O_D0001.V0003_C01_META
or $ readump_l3at_data HALOE_L3AT_SH2O_D0001.V0003_C01_META (C program)
-
-
- Name:
- Help Desk
- Addresses:
- NASA Goddard Space Flight Center
- Code 610.2
- Greenbelt, MD 20771
- Telephone Numbers:
- Phone: 1-301-614-5224
- FAX: 1-301-614-5268
- Electronic Mail
Address:
- daacuso@daac.gsfc.nasa.gov
-
-
The UARS HALOE data are archived at the GSFC DAAC, and can be
identified by the attributes listed below.
Data Set = UARS
Data Product = HALOE L3AT DAILY TIME ORDERED
-
-
The HALOE level 3A data files can be obtained from the Goddard DAAC
by several mechanisms. These include the following:
-
Anonymous
FTP. The most recent month of HALOE data (about 2
months from current) can be down loaded from the DAAC anonymous
FTP server located at daac.gsfc.nasa.gov, in directory
http://disc.sci.gsfc.nasa.gov/data/uars/haloe. This area can also
be accessed through the World Wide Web at
ftp://daac.gsfc.nasa.gov/data/uars/haloe. For convenience, the
data files are arranged in directories by instrument, level,
subtype, year and month (e.g.
http://disc.sci.gsfc.nasa.gov/data/uars/haloe/3at/hcl/1997/10).
-
The DAAC Web-Based Archive
Interface provides a means for searching and
ordering data. To search the data holdings and place an order,
go to the DAAC Home Page located at "/index.shtml", and click
on the "Search and Order" icon. Next, pick the "Data Set" link,
and from there choose "UARS".
-
Earth
Observing System Data Gateway (EDG). You can place
orders for the UARS data through the Earth Observing System
(EOS) Data Gateway. From here you can also order data products
from other data centers. The web address for the EDG is
"http://eos.gsfc.nasa.gov/imswelcome/".
- DAAC Help
Desk. Data can also be obtained by contacting the
GSFC DAAC Help Desk listed above.
Data can be ordered electronically (FTP).
-
- The DAAC currently supports HALOE level 2 and 3AT data
products.
The HALOE level 3A data are available. See the section above on Procedures for
Obtaining Data for specific information. For more information on
HALOE, please refer to the HALOE Home Page.
-
-
- Reber, C. A., C. E. Trevathan, R. J. McNeal, and M. R. Luther,
The Upper Atmosphere Research Satellite (UARS) Mission, J. Geophys.
Res. 98, D6, 10643-10647, 1993.
-
-
A list of relevant journal
articles is available on the HALOE Home Page.
Hervig, M.E., J. M. Russell III, L. L. Gordley, J. H. Park, and
S. R. Drayson, Observations of Aerosol by the HALOE Experiment
Onboard UARS: A Preliminary Validation, Geophysical Research
Letters, 20, No. 12, 1291-1294, June 18, 1993
Russell, James M., III, Gordley, Larry L., Park, Jae H.,
Drayson, S. Roland, Hesketh, W. Donald, Cicerone, Ralph J., Tuck,
Adrian F., Frederick, John E., Harries, John E., and Paul J.
Crutzen, "The Halogen Occultation Experiment," Journal of
Geophysical Research, vol. 98, no. D6, June 20, 1993
-
-
HALOGEN OCCULTATION
EXPERIMENT (HALOE), NURSHA03.
Horne, C.,
UARS Granule Level File (*META) Description, July 1994.
-
- DATA PRODUCT
-
A collection of parameters packaged with associated ancillary and
labeling data. Uniformly processed and formatted. Typically uniform
temporal and spatial resolution. HALOE level 3A data products
include HALOE_L3AL_DAILY and HALOE_L3AT_DAILY. The HALOE data
product class is divided into data product subclasses according to
measured parameters.
- DATA SET
-
A logically meaningful grouping or collection of similar or related
data. Data having mostly similar characteristics (source or class
of source, processing level and algorithms, etc.) HALOE is a subset
of the UARS data set.
- GRANULE
-
A Granule is the smallest aggregation of data which is
independently managed.
- PARAMETER
- A measurable or derived variable represented by the data (e.g.
air temperature, snow depth, relative humidity). At the Goddard DAAC,
parameters are grouped into a Parameter General category, which is
broken down into Parameter Specific.
CDHF |
Central Data Handling Facility |
CH4 |
methane |
CO2 |
carbon dioxide |
DAAC |
Distributed Active Archive Center |
DCF |
Data Capture Facility |
EOS |
Earth Observing System |
FOV |
field of view |
GSFC |
Goddard Space Flight Center |
H2O |
water vapor |
HCl |
hydrogen chloride |
HF |
hydrogen fluoride |
hPa |
hecto-pascal |
IMS |
Information Management System |
JPL |
Jet Propulsion Laboratory |
K |
Kelvin |
km |
kilometer |
LOS |
line of sight |
m |
meter |
mb |
millibar |
HALOE |
Halogen Occultation Experiment |
NASA |
National Aeronautics and Space Administration |
NMC |
National Meteorological Center |
NO |
nitric oxide |
NO2 |
nitrogen dioxide |
O3 |
ozone |
PI |
Principal Investigator |
ppmv |
parts per million by volume |
RAC |
Remote Analysis Computer |
SFDU |
Standard Formatted Data Units |
TDRSS |
Tracking and Data Relay Satellite System |
UARS |
Upper Atmosphere Research Satellite |
USO |
User Services Office |
-
-
- 19 February 1998
-
-
-
-
-
- /DATASET_DOCS/uars_haloe_l3at_dataset.html
UARS Project
Change History
- Version 2.0
- Version baselined on addition to the GES Controlled Documents
List, February 19, 1998.
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