# Presentation: 753298

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

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

**Phil Russell****1****, Peter Pilewskie****2****, **** Jens Redemann****3****, John Livingston****4****, Beat Schmid****3****, Ralph Kahn****5****, Allen Chu****6****, Jim Eilers****1****, John Pommier****3****, Steve Howard****3****1****NASA Ames Research Center, ****2****U. Colorado, ****3****Bay Area Environmental Research Institute, ****4****SRI International, ****5****Jet Propulsion Laboratory, ****6****NASA Goddard Space Flight Center**

**AMS ASAAQ Conference, ****San Francisco, CA, 27-29 April 2005**

**J31**

## ICARTT: International Consortium for Atmospheric                           Research on Transport & Transformation

**ICARTT: ****International Consortium for Atmospheric ****                          Research on Transport & Transformation**

**INTEX: NASA**

**ITCT: NOAA**

**J31**

## 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

_**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**

**J31 in INTEX-ITCT – Aerosol **_**Direct & Indirect**_** Radiative Effects **

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

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

**Nearly All The Important Aerosol Types****Good Mix of Cloudy & Clear Conditions—Direct & Indirect**_** **_

## P3

**P3**

**J31**

**Ronald H. Brown & Chebogue Point**

**Satellites**

**NOAA Lidar**

**DC8**

## Jetstream-31 (J31) in INTEX-ITCT

**Ames Earth Science Seminar**
**7 Oct 2004**

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

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

_**Jetstream-31 in INTEX-ITCT**__** **_

_**Measures**_**: ****Solar direct-beam transmission, T, at 14 wavelengths, ********, 353-2139 nm**
_**Data products**_
**Aerosol optical depth (AOD) at 13 ********, 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**

- }

## 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**

**Notes:**
Instrument specs; we measure flux/irradiance with hemispheric fov for radiation budget analysys. Narrow fov more appropriate for remote sensing.

## J31 Science Objectives

**Validate Satellites (AOD spectra, H****2****O columns)**
**Test Closure (Consistency) among Suborbital Results**
**Test Chemical-Transport Models Using AOD Profiles**
**Assess Regional Radiative Forcing by Combining Satellite and Suborbital Results**

**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**

_**Joint AATS-SSFR**_

_**AATS**_

_**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**

## J31 deployment for INTEX-ITCT/2004

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

**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**_**.**

## J31 Science Objectives

**Validate Satellites (AOD spectra****, H****2****O columns)**
**Test Closure (Consistency) among Suborbital Results**
**Test Chemical-Transport Models Using AOD Profiles**
**Assess Regional Radiative Forcing by Combining Satellite and Suborbital Results**

**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**

_**Joint AATS-SSFR**_

_**AATS**_

_**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**

## J31 Science Objectives

**Validate Satellites (AOD spectra****, H****2****O columns)**
**Test Closure (Consistency) among Suborbital Results**
**Test Chemical-Transport Models Using AOD Profiles**
**Assess Regional Radiative Forcing by Combining Satellite and Suborbital Results**

**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**

_**Joint AATS-SSFR**_

_**AATS**_

_**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**

## 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**

## MISR observing concept

**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**

## Five Years of MISR Global Aerosol Products

_**Mid-vis AOT**_
**• ****Land & Water **
**• ****Bright Surfaces**
**• ****Globe ~ weekly**
**• ****~ 10:30 AM**
**+ particle **
**    ****size, shape**

**Kahn**

## Kahn

**Kahn**

## Kahn

**Kahn**

## Kahn

***2 Aircraft in Clear**

*****

**Kahn**

**Notes:**
Path 8		Target 43N, 65W
Path 9		Target 43N, 67W
Path 10		Target 43N, 68W
Path 11		Target 43N, 69W
Path 12		Target 43N, 71W

## 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**

**Notes:**
July 22

## MISR Aa 

- MISR Aa
- Level 1B2 RGB
**July 22**, 2004
- Orbit 24440
- Blocks 55-58
- 1.1 km resolution

**Kahn**

## Livingston, Kahn, ...

- From: The AATS Team

**Livingston, Kahn, ...**

**MISR **
**Grid Boxes**

## AGU poster: MISR V15

- From: The AATS Team

**Livingston, Kahn, ...**

## MISR V16: Matlab run 11 Feb 2005

**Livingston, Kahn, ...**

## Kahn

**Kahn**

**Notes:**
To the north and east, aerosol mixtures 6 (spherical, medium, clean) and 9 (spherical, bi-modal, clean) dominate
To the west, mixtures 1, 2 (spherical, small, clean), 10 (spherical, bi-modal, clean), and especially 18, 19 (dusty) are common
In situ observations: Sep 01 -- 50% by mass more fine mode than any other campaign day
Sep 10 -- Average day for campaign, with a little more dust
Sep 12 -- Highest AOT day of campaign; 2x higher Fe in particles

## Livingston, Kahn...

**Terra overpass: 1531 UT**

- small AOD gradient (AATS)

**Livingston, Kahn...**

**MISR **
**Grid Boxes**

## Livingston, Chu...

- small AOD gradient (AATS)

**Livingston, Chu...**

**MODIS **
**Grid Boxes**

## Livingston, Kahn, Chu, ...

**Livingston, Kahn, Chu, ...**

## Satellite AOD Validation in INTEX-ITCT

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

_**This type of analysis is in progress for**_

## J31 Science Objectives

**Validate Satellites (AOD spectra, H****2****O columns)**
**Test Closure (Consistency) among Suborbital Results**
**Test Chemical-Transport Models Using AOD Profiles**
**Assess Regional Radiative Forcing by Combining Satellite and Suborbital Results**

**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**

_**Joint AATS-SSFR**_

_**AATS**_

_**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**

## 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**

**Smoke ****from ****Alaskan ****Wildfires**

**Downwelling solar energy [W m****-2****]**

**Aerosol Amount, AOD(499 nm)**

**MODIS Aqua, 21 July 2004, 1805 UT**

**Jetstream 31 ****21 July 2004, 1815-1820 UT**

**Slope: ****Aerosol Radiative ****Forcing Efficiency**

**Redemann, Pilewskie, ...**

## Methodology for studying aerosol radiative forcing from horizontal gradients 

**Measure simultaneous change in spectral aerosol optical depth (AATS-14) and spectral net irradiance (SSFR) →****	**** ********F****net****/********AOD = 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, ...**

## J31 Flight 12, 21 July 2004

- _J31 Flight 12, 21 July 2004_

- Slope, F/AOD,
- is forcing efficiency

**Redemann, Pilewskie, ...**

## 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, ...**

## Redemann, Pilewskie, ...

**Redemann, Pilewskie, ...**

**AOD(499 nm)**

**Flux Change**

## Redemann,

**Redemann,**
**Pilewskie**

## Forcing Efficiency, F/AOD499

**Forcing Efficiency, ********F/********AOD****499**

**Redemann, Pilewskie, ...**

**Case No.**

## Relative Forcing Efficiency [%]

**Relative Forcing Efficiency [%]**

**Redemann, Pilewskie, ...**

**Case No.**

## Relative Forcing 

**Relative Forcing **
**Efficiency [%]**

**Forcing **
**Efficiency **

**Change in Column Water Vapor [cm]**

**Rede- **
**mann, **
**Pilew- **
**skie**

## Angstrom  

**Angstrom ******** **

**Particle size **

**Relative Forcing **
**Efficiency [%]**

**Forcing **
**Efficiency **

**Redemann, Pilewskie**

## Gradient forcing work 

**Next: Quantify and correct for solar zenith angle effects**
**For 11 best cases, instantaneous ********F****net****,****Vis****/********AOD****499****, **_**mean**_** is **_**-103 W m**__**-2**_** or **_**-22%**_** of F****down****.**
** **
**Previous field campaigns: instantaneous ********F****net****,****Vis****/********AOD****500    ****(converted to **_**noontime**_** equivalent)**

**Redemann, Pilewskie, ...**

***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**

## Summary & Outlook

**Comparisons of AATS AOD spectra to MISR & MODIS results are helping to **_**improve satellite retrievals**_** and cloud screening.**
_**Aerosol radiative forcing efficiency,**_** ********F/********AOD, 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 F**__**down**_**.** **Published values from INDOEX: -84 to -156 W m****-2**** . [All per ********AOD****midvis****]**
**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.**

## 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.**

## End of Presentation(Remaining slides are backup)

## The Investment in the J31 (A Catalog Aircraft)

**	****  ****EOS IDS=Earth Obs. Sys. Inter-Disciplinary Science**

**The Investment in the J31**_** **_**(A Catalog Aircraft)**

| 
Task | NASA |  |  |  |  | NOAA |
| --- | --- | --- | --- | --- | --- | --- |
|  | 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 | ■ |  |  |  | ■ |  |

## 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.

## Slide 46

## Redemann, Pilewskie, ...

**Redemann, Pilewskie, ...**

## Redemann, Pilewskie, ...

**Redemann, Pilewskie, ...**

## Redemann, Pilewskie, ...

**Redemann, Pilewskie, ...**