AIRBORNE SUNPHOTOMETER AND SOLAR SPECTRAL FLUX RADIOMETER MEASUREMENTS DURING INTEX/ITCT 2004

1
AIRBORNE SUNPHOTOMETER AND SOLAR SPECTRAL FLUX
RADIOMETER MEASUREMENTS DURING INTEX/ITCT 2004
Phil Russell1, Peter Pilewskie2, Jens
Redemann3, John Livingston4, Beat Schmid3, Ralph
Kahn5, Allen Chu6, Jim Eilers1, John Pommier3,
Steve Howard31NASA Ames Research Center, 2U.
Colorado, 3Bay Area Environmental Research
Institute, 4SRI International, 5Jet Propulsion
Laboratory, 6NASA Goddard Space Flight Center
J31
AMS ASAAQ Conference, San Francisco, CA, 27-29
April 2005
2
ICARTT International Consortium for Atmospheric
Research on Transport
Transformation
J31
ITCT NOAA
INTEX NASA
3
J31 in INTEX-ITCT Aerosol Direct Indirect
Radiative Effects

• GOALS
• Assess the radiative impact of the aerosols
  advecting from North America out over the
  Northwestern Atlantic Ocean.
• Clear-sky Impact Aerosol Direct Effect
• Impact Via Clouds Aerosol Indirect Effect
• Quantify the relationships between those
  radiative impacts and aerosol amount and type.
• Contribute water spectral albedo measurements to
  help improve satellite aerosol retrievals

4
INTEX-ITCT-ICARTT Provides a Very Fertile Context
For Aerosol-Climate Studies

• Nearly All The Important Aerosol TypesGood Mix
  of Cloudy Clear ConditionsDirect Indirect

5
Satellites
P3
NOAA Lidar
DC8
J31
Ronald H. Brown Chebogue Point
6
Jetstream-31 (J31) in INTEX-ITCT
Ames Earth Science Seminar 7 Oct 2004
7
Jetstream-31 in INTEX-ITCT

• 14-channel Ames Airborne Tracking
• Sunphotometer (AATS-14)

• Measures Solar direct-beam transmission, T, at
  14 wavelengths, l, 353-2139 nm
• Data products
• Aerosol optical depth (AOD) at 13 l, 353-2139 nm
• Water vapor column content using T(940 nm)
• Aerosol extinction,
• 340-2139 nm
• Water vapor
• density

• When
• A/C
• flies
• vertical
• profiles

8
NASA Ames Solar Spectral Flux Radiometer (SSFR)

• wavelength range
• 300 nm to 1700 nm
• spectral resolution
• 8-12 nm
• simultaneous zenith
• and nadir viewing
• hemispheric FOV
• Accuracy 3 precision 0.5
• Missions FIRE/SHEBA, DOE ARM UAV (1999, 2000,
  2002), PRIDE, SAFARI-2000, ACE-Asia,
  CRYSTAL-FACE, DOE Aerosol IOP

Pilewskie
9
J31 Science Objectives
AATS

• Validate Satellites (AOD spectra, H2O columns)
• Test Closure (Consistency) among Suborbital
  Results
• Test Chemical-Transport Models Using AOD Profiles
• Assess Regional Radiative Forcing by Combining
  Satellite and Suborbital Results

SSFR

• Retrieve cloud droplet radius, optical depth, and
  liquid water path
• Compare/validate with P-3 MIDAS, P-3
  microphysics, satellite retrievals (MODIS),
  microwave/radar retrievals from the Ron Brown.
• Relate these cloud properties to near-cloud
  aerosol properties (from other investigators and
  platforms)
• Provide water spectral albedo measurements to
  help improve satellite aerosol retrievals

Joint AATS-SSFR

• Study effect of over-cloud AOD on cloud property
  retrievals by SSFR and satellites
• Derive Spectra of Aerosol Absorbing Fraction
  (1-SSA) from Spectra of Radiative Flux and AOD.
• Derive Aerosol Radiative Forcing from
  Simultaneously Measured Radiative Flux and AOD
  Gradients

10
J31 deployment for INTEX-ITCT/2004
? 19 Science Flights out of Portsmouth, NH, 12
Jul-8 Aug ? 58.4 Flight Hours ? Flights
coordinated with satellites Terra Aqua, Ron
Brown its sondes, DC-3, DC-8, P-3 ? J31,
AATS, SSFR, Met, Nav Systems all performed very
well.

• Survey Vertical Profile.
• Minimum- Altitude Transect.
• (3) Parking Garage.
• (4) Above-Cloud Transect.

11
J31 Science Objectives
AATS

• Validate Satellites (AOD spectra, H2O columns)
• Test Closure (Consistency) among Suborbital
  Results
• Test Chemical-Transport Models Using AOD Profiles
• Assess Regional Radiative Forcing by Combining
  Satellite and Suborbital Results

SSFR

• Retrieve cloud droplet radius, optical depth, and
  liquid water path
• Compare/validate with P-3 MIDAS, P-3
  microphysics, satellite retrievals (MODIS),
  microwave/radar retrievals from the Ron Brown.
• Relate these cloud properties to near-cloud
  aerosol properties (from other investigators and
  platforms)
• Provide water spectral albedo measurements to
  help improve satellite aerosol retrievals

Joint AATS-SSFR

• Study effect of over-cloud AOD on cloud property
  retrievals by SSFR and satellites
• Derive Spectra of Aerosol Absorbing Fraction
  (1-SSA) from Spectra of Radiative Flux and AOD.
• Derive Aerosol Radiative Forcing from
  Simultaneously Measured Radiative Flux and AOD
  Gradients

12
J31 Science Objectives
AATS

• Validate Satellites (AOD spectra, H2O columns)
• Test Closure (Consistency) among Suborbital
  Results
• Test Chemical-Transport Models Using AOD Profiles
• Assess Regional Radiative Forcing by Combining
  Satellite and Suborbital Results

SSFR

• Retrieve cloud droplet radius, optical depth, and
  liquid water path
• Compare/validate with P-3 MIDAS, P-3
  microphysics, satellite retrievals (MODIS),
  microwave/radar retrievals from the Ron Brown.
• Relate these cloud properties to near-cloud
  aerosol properties (from other investigators and
  platforms)
• Provide water spectral albedo measurements to
  help improve satellite aerosol retrievals

Joint AATS-SSFR

• Study effect of over-cloud AOD on cloud property
  retrievals by SSFR and satellites
• Derive Spectra of Aerosol Absorbing Fraction
  (1-SSA) from Spectra of Radiative Flux and AOD.
• Derive Aerosol Radiative Forcing from
  Simultaneously Measured Radiative Flux and AOD
  Gradients

13
ICARTT 2004 AATS-14/MODIS Coincidences

• Eight cases w/MODIS data
• July 12, 16, 17, 21, 22, 23 August 2, 8

ICARTT 2004 AATS-14/MISR Coincidences

• Four events
• July 20, 22, 29 August 7

Livingston
14
MISR observing concept
Nine view angles at Earth surface 70.5º forward
to 70.5º aft Four spectral bands at each
angle 446, 558, 672, 866 nm Seven minutes to
observe each scene at all 9 angles 400-km
swath Global coverage about once per week 275
m - 1.1 km spatial sampling Air mass factors
from 1 (nadir) to 3 Scattering angles from 60
to 160 in mid-latitudes
Kahn
15
Five Years of MISR Global Aerosol Products
Mid-vis AOT Land Water Bright Surfaces
Globe weekly 1030 AM particle size,
shape
Kahn
16
Kahn
17
Kahn
18

2 Aircraft in Clear
Kahn
19
22 July
MISR Coverage Map Path 010 Blocks 55-58 July
22 -- DC-8 11 J-31 13 Aug 07 -- DC-8 17
J-31 22
Kahn
20
MISR Aa Level 1B2 RGB July 22, 2004 Orbit
24440 Blocks 55-58 1.1 km resolution
Kahn
21
MISR Grid Boxes
Livingston, Kahn,
From The AATS Team
22
AGU poster MISR V15
Livingston, Kahn,
From The AATS Team
23
MISR V16 Matlab run 11 Feb 2005
Livingston, Kahn,
24
Kahn
25
Terra overpass 1531 UT
small AOD gradient (AATS)
MISR Grid Boxes
Livingston, Kahn
26
MODIS Grid Boxes
small AOD gradient (AATS)
Livingston, Chu
27
Livingston, Kahn, Chu,
28
Satellite AOD Validation in INTEX-ITCT
This type of analysis is in progress for

• 3 more MISR cases
• 7 more MODIS cases
• Includes work on cloud screening

29
J31 Science Objectives
AATS

• Validate Satellites (AOD spectra, H2O columns)
• Test Closure (Consistency) among Suborbital
  Results
• Test Chemical-Transport Models Using AOD Profiles
• Assess Regional Radiative Forcing by Combining
  Satellite and Suborbital Results

SSFR

• Retrieve cloud droplet radius, optical depth, and
  liquid water path
• Compare/validate with P-3 MIDAS, P-3
  microphysics, satellite retrievals (MODIS),
  microwave/radar retrievals from the Ron Brown.
• Relate these cloud properties to near-cloud
  aerosol properties (from other investigators and
  platforms)
• Provide water spectral albedo measurements to
  help improve satellite aerosol retrievals

Joint AATS-SSFR

• Study effect of over-cloud AOD on cloud property
  retrievals by SSFR and satellites
• Derive Spectra of Aerosol Absorbing Fraction
  (1-SSA) from Spectra of Radiative Flux and AOD.
• Derive Aerosol Radiative Forcing from
  Simultaneously Measured Radiative Flux and AOD
  Gradients

30
MODIS Aqua, 21 July 2004, 1805 UT
Climate Change Science in INTEX Aircraft
Satellite Measurements of Aerosol Effects on the
Solar Energy that Drives Climate
Slope Aerosol Radiative Forcing Efficiency
Downwelling solar energy W m-2
Smoke from Alaskan Wildfires
Jetstream 31 21 July 2004, 1815-1820 UT
Aerosol Amount, AOD(499 nm)
Redemann, Pilewskie,
31
Methodology for studying aerosol radiative
forcing from horizontal gradients

• Measure simultaneous change in spectral aerosol
  optical depth (AATS-14) and spectral net
  irradiance (SSFR) ? DFnet/DAOD aerosol
  radiative forcing (efficiency)
• Observationally-based estimate of aerosol
  radiative effect
• Advantage over ground-based methods
  quasi-instantaneous possibly scientific First
• Need to check (and correct for) effects of
  changing solar zenith angle

Redemann, Pilewskie,
32
J31 Flight 12, 21 July 2004
Slope, DF/DAOD, is forcing efficiency
Redemann, Pilewskie,
33
Progress on gradient forcing work

• Identified 16 cases of observed AOD gradients
  during low-level J-31 legs
• QA for AATS and SSFR data
• Checked for surface effects by looking at
  down-welling and net irradiance separately
• Extended analysis to forcing efficiencies in 7
  SSFR channels (380, 506, 762, 940, 1052, 1201,
  1604nm)
• Computed relative forcing efficiencies, i.e.,
  forcing efficiency divided by down-welling
  irradiance in each SSFR channel
• Looked at forcing efficiencies as f(CWV) and
  f(particle size)

Redemann, Pilewskie,
34
Flux Change
Redemann, Pilewskie,
AOD(499 nm)
35
Redemann, Pilewskie
36
Forcing Efficiency, DF/DAOD499
Case No.
Redemann, Pilewskie,
37
Relative Forcing Efficiency
Case No.
Redemann, Pilewskie,
38
Forcing Efficiency
Relative Forcing Efficiency
Rede- mann, Pilew- skie
Change in Column Water Vapor cm
39
Forcing Efficiency
Relative Forcing Efficiency
Angstrom a
Redemann, Pilewskie
Particle size
40
Gradient forcing work

• Next Quantify and correct for solar zenith angle
  effects
• For 11 best cases, instantaneous
  DFnet,Vis/DAOD499, mean is -103 W m-2 or -22 of
  Fdown.
• Previous field campaigns instantaneous
  DFnet,Vis/DAOD500 (converted to noontime
  equivalent)

• Jayaraman et al. JGR 1998, Pre-INDOEX '96
• -156 15 W m-2
• Meywerk Ramanathan JGR 1999, INDOEX '98
• -84 W m-2
• Bush Valero JGR 2002, INDOEX '99
• -113 8 W m-2, -104 24 W m-2

Redemann, Pilewskie,
41
Summary Outlook

• Comparisons of AATS AOD spectra to MISR MODIS
  results are helping to improve satellite
  retrievals and cloud screening.
• Aerosol radiative forcing efficiency, DF/DAOD,
  has been determined for many cases when J31 flew
  across AOD gradients
• Within 11 cases we found a high variability in
  instantaneous aerosol forcing efficiency. For
  net flux, 350 - 700 nm, the mean was -103 W m-2
  or -22 of Fdown. Published values from INDOEX
  -84 to -156 W m-2 . All per DAODmidvis
• The large and varied data set from the J31 is
  being used to address many other goals not
  covered here, including aerosol indirect effects,
  ocean surface albedo, water vapor retrievals,
• The J31 and its ICARTT 2004 payload are well
  suited to address the radiative-climatic goals of
  INTEX-B (including effects of Asian outflow on
  the US west coast). Our proposal for J31
  participation in INTEX-B is pending.

42
Low-altitude aircraft flight patterns proposed
for INTEX-B studies of aerosol radiative effects
and satellite validation
(1) Survey Vertical Profile. (2)
Minimum-Altitude Transect. (3) Stepped Profile
(Parking Garage) (4) Above-Cloud Transect.
43
End of Presentation(Remaining slides are backup)
44
The Investment in the J31 (A Catalog Aircraft)
Task NASA NASA NASA NASA NASA NOAA
Task RSP TCP SSP AA SF EOS IDS ACCP
Modify J31 for AATS, SSFR, Met, Nav
Purchase Met Sensors (T, Td, Pstat, Ptot)
Borrow Nav System
Develop Met/Nav Data System
Install Test all above (ground flight)
Deployment, flight hrs, crew travel,
Measurements
- AATS (includes MLO calibrations)
- SSFR
Data Reduction Archival
Integrated Analyses
Programs RSPRad. Sci., TCPTrop. Chem.,
SSPSuborb. Sci., AASFAmes Airborne Sens.
Facil., ACCPAtmos. Comp. Clim. EOS
IDSEarth Obs. Sys. Inter-Disciplinary Science
45
ICARTT J31 Findings, Cloud/Indirect Effects
Surface Albedo

• 1. a few cases identified for direct comparison
  between SSFR/MIDAS retrievals of cloud droplet
  size, cloud optical thickness, and cloud water
  path need to compare with in situ (FSSP on P-3)
  and satellite derived r_e, tau.
• 2. Several (at least 3?) J-31 cases of cloud
  spectral reflectance measured in regions of
  enhanced aerosol loading over clouds. Need to be
  examined in context of direct and indirect
  radiative forcing and influence on cloud
  retrievals from space
• 3. Measured  water-leaving irradiance in Gulf of
  NH shows water to be very "black", i.e.,
  relatively low levels of chlorophyll-A.
• 4. Sea surface spectral albedo/water-leaving
  irradiance needs to be adapted for use with MISR
  data for constraining low level AOT algorithms
  convert to water-leaving radiance via BRDF.

46
(No Transcript)
47
Redemann, Pilewskie,
48
Redemann, Pilewskie,
49
Redemann, Pilewskie,