Introduction
The Halogen Occultation Experiment (HALOE) is one of 10 instruments
aboard the Upper Research Satellite (UARS).
The HALOE instrument was built by an instrument team based at
NASA Langley and launched on the UARS on 12th September 1991.
Data collection began on 11th October 1991 until 21st November 2005.
The Principal Investigator (PI) is Dr James M. Russell III.
The HALOE experiment uses solar
occultation to measure vertical profiles of ozone (O3), hydrogen chloride (HCl),
Hydrogen Fluoride (HF), methane (CH4), water vapour (H2O), nitric oxide (NO), nitrogen dioxide (NO2),
aerosol extinction, and temperature versus pressure
with an instantaneous vertical field of view of 1.6 km at the
Earth limb.
The instrument achieves near-global coverage
with measurements sweeping between high latitudes in one hemisphere
and high latitudes in the other over a period of between 2 and
6 weeks. The latitude range covered by the instrument varies over
the course of the year between 80°S and 80°N.
The maximum northerly and southerly latitudes occur in spring
and autumn in the few weeks either side of the equinoxes. The
range of altitude of the measurements depends on the channel being
used, but measurements cover the stratosphere and lower mesosphere
and, in the case of the nitric oxide channel, extend into the
lower thermosphere.
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 analyse in detail the development
and recovery of the Antarctic ozone hole. Additional studies are
intended to identify and assess stratosphere-troposphere exchange.
The BADC holds HALOE data at level 2 (uninterpolated
profiles at measurement locations), version 19 for the period 11th Ocotber 1991 to 21st November 2005.
The BADC also holds the HALOE level 3A version 19 data spanning the time period from 11th October 1991 through 21st December 2000. HALOE L3 data is public. Updates through to September 24, 2001 are available directly from GSFC NASA.
The HALOE level 3A data are vertical profiles of methane (CH4), hydrogen chloride (HCl), hydrogen
fluoride (HF), nitric oxide (NO), nitrogen dioxide (NO2), water vapor (H2O),
ozone (O3), temperature (TEMP), and aerosol extinction (AEXTCH4, AEXTHCL,
AEXTHF and AEXTNO), interpolated onto a standard set of
vertical levels evenly spaced in pressure, and onto standard times (level 3AT) and standard latitudes (level 3AL). The vertical scan range is from about 10 to 65 km, and the
vertical resolution is approximately 2.5 km between pressure levels.
Access Restrictions
- Access to HALOE Level 2
Dr James Russell
(PI) wishes to monitor the use of the HALOE Level 2 data and requires an acknowledgement
of the data source if they are used in any publication. In order
to gain access to the HALOE Level 2 data and accompanying software, please
apply for access to HALOE Level 2 data .
Your application for accessing the Haloe Level-2 data will be processed
within a day of receipt. Provided your application is complete
and Dr Russell has granted you access to the data, a web
account will be activated to allow access
to the HALOE L2 data directories via your login account from the BADC WWW
Browse Archive pages.
- Access to HALOE Level 3
HALOE data at level 3A and version 19 are public and
the HALOE Level 3A data directories can be accessed directly over the web.
Please read the 00README
file available under /badc/haloe/ directory to guide you through
the tree structure and the data directory.
Documentation, Links to further information and references
The BADC provides several documents to help you use this dataset.
These include the full set of documentation
produced by the instrument team at NASA Langley, as well as
a help file written at the BADC which
contains an overview of the instrument, measurement techniques
and the species measured, including details of coverage, resolution
and data quality.
You may browse the HALOE
Homepage from which you may also download the data in netCDF format (compressed with Gzip). The HALOE version 19 Image Selector is also available from this website.
The HALOE L3A Version 19 data are originally available from the GSFC NASA.
The HALOE instrument is described in Russell et al. (1993)
J. Geophys. Res. 98 D6, pp. 10777 -
10797. Some early results from HALOE are described in the UARS
special issue of the Journal of Atmospheric Science (vol 51 no.
20).
We provide a list of references
to papers using HALOE data and a list of references to other
UARS paper.
A continuously updated list of references is available from the HALOE NASA webpage.
Citation
National Aeronautics and Space Administration, Langley, [Russell, J.; Harries, J.]. Halogen Occultation Experiment (HALOE), [Internet]. NCAS British Atmospheric Data Centre, 2006-, Date of citation. Available from http://badc.nerc.ac.uk/view/badc.nerc.ac.uk__ATOM__dataent_HALOE .
Who to contact
For general queries about these pages or about browsing the
data, you should contact the BADC support
line.
For further information about the data or the instrument contact
the HALOE Principal Investigator James
Russell or his team at NASA Langley. Prof. John
Harries at Imperial College, London is a UK Co-Investigator.
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