# Presentation: 272682

## Radicals + HCHO Column

| Species | Column | Profile | Sub-orbital | Speaker |
| --- | --- | --- | --- | --- |
| NO2 | OMI |  | Ground based column | Brinksma, Celarier, Sander |
| HCHO | OMI |  | Aircraft | Millet, Kursou |
| BrO | OMI | MLS | Plenty, but none discussed | Livesey, Kurosu |
| OClO | OMI |  | Plenty, but none discussed | Kurosu |
| OH |  | MLS | Balloon & ground based column | Sander, Canty |
| HO2 |  | MLS | Balloon | Canty |

## Dylan Millet – DC-8 HCHO analysis

- • High column HCHO is good indicator of isoprene production
- • Isoprene production is important for VOC inventory in air quality models
- • Presently working with DC-8 data from ICART
- • A/C data simulations indicate that clouds will be the largest error source
-       in retrieving accurate HCHO columns from satellite data

- • Ready to begin comparing DC-8 HCHO profiles to OMI HCHO columns

## Nathaniel Livesey – MLS BrO profiles

- • MLS Vers 1.5 BrO product not for scientific use
- • Special BrO retrievals, using averaged radiances, being studied
- • MLS BrO < SLIMCAT BrO at altitude of peak BrO; MLS BrO often
-     greater than SLIMCAT BrO elsewhere (e.g, MLS has broader distrib.)

- • Above results ***very preliminary*** and subject to change, pending
-      improvements in BrO retrievals
- • Suborbital data for validation needed:
-         – NASA aircraft data could be used in “Bry vs tracer space”
-         – European balloon (e.g, DOAS, SAOZ) BrO profiles

## Thomas Kurosu – OMI Column BrO, HCHO, and OClO

- • OMI BrO has fitting errors of 20-40% for background and ~4% in “hot spots”
- • See “bromine explosions” in SH, Sept 2004, near thin sea ice
- • See BrO hot spots over Dead Sea and Salt Lake, Utah

- • Monthly and daily HCHO product from OMI maturing
-         – global vertical HCHO column for July 2005 shown
- • OClO product starting to emerge
- • L2 OMI BrO, HCHO, and OClO product from Kurosu’s Harvard-Smithsonian CfA
-      group will soon be submitted to AVDC

## Ed Celarier – OMI NO2

- • OMI NO2 retrievals (~1:30 LST) compared to ground based, sunrise & sunset data
- • Comparisons overall promising, but some ground based instruments (e.g. DOAS,
-     SAOZ) not sensitive to tropospheric NO2
- • Cede and Herman have developed method for ground based NO2, using GSFC
-     Brewer instrument, that is sensitive to tropospheric NO2

- • Comparisons for many more stations were shown
- •  Prefer sub-orbital data that can distinguish stratospheric & tropospheric column NO2

## Ellen Brinksma – Ground Based NO2 Data Sources

- Ellen Brinksma – Ground Based NO2 Data Sources

- • Extensive ground based NO2 data from Cabauw, Netherlands (51°N) for validation
-      of OMI and SCIAMACHY
- • Mobile Lidar + 5 MAX DOAS + in situ NO2 instruments
- • 5 “golden days” of data: 27-28 May, 19, 23, 24 June 2004; continuous data is
-      available from most MAX DOAS instruments
- •  MAX DOAS very sensitive to tropospheric NO2

- •  Good comparisons vs SCIA NO2 column
- •  Ready to begin comparing to OMI NO2 columns

## Stan Sander – Ground Based OH, NO2 and NO3 Columns

- • Observations from Table Mountain, Calif (34.4°N)
- • Extremely high spectral resolution for NO2 provides sensitivity to total column
- • Data available for most days with “clear sky” since Aura launch, and many years prior
- • New OH column retrieval uses 5 lines vs old retrieval with 1 line
-         – good overall agreement, with smaller “peak OH” for new retrieval
-         – diurnal asymmetry (peak ~30 minutes after noon LST) measured and modeled
- •  Absolute NO2 column available, *throughout the sunlit day*, for Aura validation
-         – 2 level retrieval possible, using pressure broadening

- •  NO3 total column (moonlight obs.) & bdry layre (active DOAS) available for SAGE III validation
- •  Data will be sent to AVDC after version 2 processing

## Tim Canty – OH and HO2 profiles, OH Columns

- • Compared MLS OH, HO2 with balloon profiles
-         – differences generally within combined Measurement Uncertainties
-         – MLS data consist of 15 day averages
-         – Oscillation in HO2 profile (all altitudes) and OH profile (Z > 65 km) under inviestigation
-            by MLS retrieval team
- • Measured OH less than modeled OH above 40 km
-         – Good agreement seen using I. W. Smith and Stewart (1994) rate for O + OH
- •  Unique opportunity, 23 Sept 2004, to compare column OH from MLS to 2 ground
-         based (FTUVS, PEPSIOS) and 2 balloon (BOH, FIRS-2) instruments:
-              – MLS column in good agreement with balloon columns
-              – MLS column tends to generally be higher than FTUVS (Tbl Mtn), but does match well upper
-                         envelope of FTUVS column seen on many days
-              – MLS column lower than PEPSIOS (Minschwaner) on Sept 23

## Future Plans

- • ***More comparisons of Aura radicals with sub-orbital data needed***
- • OMI L2 provisional products will soon be sent to AVDC
-         – selected ground stations and aircraft tracks
-         – will use calibrated L1B from Dutch team
-         – BrO, HCHO, OClO: from Kurosu et al. (Harvard CfA)
-         – NO2: from Gleason et al. (GSFC)
-         – after examination, public release of data to DAAC
- • NO2:
-        – compare OMI total and tropospheric column to existing ground based columns that are
-                 sensitive to both total and tropospheric NO2
-        – Brinksma, Sander, Celarier, Gleason, Bucsela
- • HCHO:
-        – compare DC-8 profiles, OMI columns, and GOME + SCIA columns
-        – Millet, Kurosu

## Future Plans

- • ***More comparisons of Aura radicals with sub-orbital data needed***
- • OClO:
-        – compare with available, ground based column data (European products)
-        – test consistency with MLS ClO, BrO, PV, T, etc.
-        – Kurosu, Canty, Livesey, Santee
- • BrO:
-       – test consistency between OMI column and MLS profiles
-                 can tropospheric BrO be inferred ?
-       – incorporate existing ER-2 data in “Bry vs tracer” space
-       – compare with available DOAS, SAOZ balloon profiles (European data)
-       – compare with ground based column & MAX DOAS profiling (European; New Zealand;
-                                                                                                 future G. Mount & S. Sander systems)
-       – Livesey, Kurosu, Wilmouth, Sander, Salawitch
- • OH, HO2 :
-       – good progress:  first paper under review
-       –compare MLS profiles to 20-21 Sept 2005 BOH, FIRS-2, SLS balloon profiles of OH and HO2
-               as well as 21 Sept 2005 ground-based column OH
-       – continued investigation of MLS profiles (20 to 80 km) vs ground based columns
-       – Pickett, Jucks, Stachnik, Sander, Canty, Salawitch, Livesey, Read