CHEM Science Team March 2000 Cloud processes near the tropopause HIRDLS will measure cloud top...
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Transcript of CHEM Science Team March 2000 Cloud processes near the tropopause HIRDLS will measure cloud top...
CHEM Science Team March 2000
Cloud processes near the tropopause
• HIRDLS will measure cloud top altitude and aerosol concentrations:
• the limb view gives high sensitivity;
• geometry used to determine altitude with fine resolution
(200 m step size; 1 km IFOV)
• May benefit from formation flying partners
Aqua, PICASSO-CENA and CloudSat
to obtain very comprehensive near-simultaneous cloud measurements and for cross-validation
.
[STS047-54-018, 20 Sep 1992, 15.5 S, 158.5 E]
Silhouette of several thunderstorms with cirrus anvil tops spreading out against the tropopause, and Pinatubo aerosol layers appearing blue above.
CHEM Science Team March 2000
Frequency of cirrus measured by HALOE
Relative frequency of occurrence of larger extinction values measured at 3.46 micron by the UARS HALOE instrument for 1993-1998.[S.Massie et al, submitted to J. Geophys. Res., 1999]
CHEM Science Team March 2000
Frequency of cirrus measured by HALOE
Relative frequency of occurrence of larger extinction values measured at 3.46 micron by the UARS HALOE instrument for 1993-1998.[S.Massie et al, submitted to J. Geophys. Res., 1999]
CHEM Science Team March 2000
Variation of limb extinction
Frequency of limb
extinction at 3.46 micron
and 121 hPa tangent
pressure measured by
HALOE for different
years.
Data are for the Indian
Ocean to the Eastern
Pacific between 30oN and
30oS.
[S.Massie et al, ‘The Effect of the 1997 El Nino on the Distribution of UpperTropospheric Cirrus’, submitted to J. Geophys. Res., 1999]
CHEM Science Team March 2000
Radiative transfer studies
HIRDLS will measure the radiation emitted in multiple spectral passbandsup to the thermosphere
Important for validating radiative transfer theory and undertaking basicresearch into radiative transfer
CHEM Science Team March 2000
(Day-Night )/Night
radiance difference
measured by CRISTA
in 1490-1560 cm-1
spectral region
Daytime enhancement is due
to a combination of H2O non-
LTE emission and tidal activity increasing daytime temperature
Radiative transfer studies
[Figure from David Edwards]
CHEM Science Team March 2000
Acquisition of atmospheric data in an extreme state
• Stratospheric chlorine levels are expected to peak during
the EOS-Chem mission.
• EOS-Chem data will be valuable for centuries into the future as
tests of model behaviour in this extreme high-chlorine state.
• Changes in ozone levels as chlorine declines and stratospheric
cooling accelerates will provide critical tests of model behaviour
and their ability to predict.
CHEM Science Team March 2000
Growth of stratospheric chlorine according to various scenarios
(from Joe Waters)
Stratospheric Chlorine
CHEM Science Team March 2000
HIRDLS Scientific Objectives
• Understand stratosphere-troposphere exchange of radiatively and chemically active constituents (including aerosols) down to small spatial scales
• Understand chemical processing, transports and mixing in the upper troposphere/lowermost stratosphere/lower overworld
• Understand budgets of quantities (momentum, energy, heat and potential vorticity) in the middle atmosphere that control stratosphere-troposphere exchange
• Determine upper tropospheric composition (with high vertical resolution)
• Provide data to improve and validate small scales in models
• Measure global distributions of aerosols and PSC’s and interannual variations
CHEM Science Team March 2000
Major HIRDLS Emphases
Small scale dynamics and transports
Troposphere - stratosphere exchange
Polar vortex filamentation
Tropical barrier leakage
Upper troposphere - lower stratosphere chemistry
O3, H2O, CFC11, CFC12, HNO3, CH4, N2O
Aerosol amounts, distributions & properties
Trends & changes
Trends of 10 radiativity & chemically active species, T, PSCs
Continuation of LIMS, SAMS, UARS
Gravity wave distributions
Sources & distributions of gravity waves, and their roles in atmospheric dynamics
CHEM Science Team March 2000
Summary of Measurement Requirements
Temperature <50 km 0.4 K precision 1 K absolute
>50 km 1 K precision 2 K absolute
Constituents O3, H2O, CH4, H2O, HNO3, NO2, N2O5, 1-5% precision
ClONO2, CF2Cl2, CFCl3, Aerosol 5-10% absolute
Geopotential height gradient 20 metres/500 km (vertical/horizontal)(Equivalent 60oN geostrophic wind) (3 m s-1)
Coverage:Horizontal - global 90oS to 90oN (must include polar night)Vertical - upper troposphere to mesopause (8-80 km)Temporal - long-term, continuous (5 years unbroken)
Resolution:Horizontal - profile spacing of 5o latitude x 5o longitude (approx 500 km)Vertical - 1-1.25 km
Temporal - complete field in 12 hours
CHEM Science Team March 2000
IGSE
IGSE
Auxiliary Filter Bank
TGSE
HIRDLS
HIRDLS Cleanroom
CHEM Science Team March 2000
Collimator/monochromator calibration equipment
CHEM Science Team March 2000
Monochromator turretSeismic isolator
Clean room and vacuum chamber Chamber optical bench
HIRDLS Calibration Facility