# Presentation: 366551

##   TOP-DOWN ESTIMATES OF VOC EMISSIONSFROM SPACE-BASED HCHO COLUMN OBSERVATIONS:FROM GOME TO OMIDaniel J. Jacob, Paul I. Palmer, Tzung-May Fu, Dylan B. Millet, Dorian S. Abbot, Solene TurquetyAtmospheric Chemistry Modeling Group, Harvard University Kelly V. Chance and Thomas KurosuHarvard/Smithsonian Center for AstrophysicsM.J. Pilling and J. Stanton (U. Leeds); S.N. Pressley and B. Lamb (Washington State U.); A.-L. Sumner and P. Shepson (Purdue); A. Guenther, A. Fried, C. Wiedinmyer (NCAR); B.G. Heikes (URI); B. Barletta (UC Irvine)

## RELATING HCHO COLUMNS TO VOC EMISSION

**VOC****i**

**HCHO**

**h******** (340 nm), OH**

**oxn.**

***k ~ 0.5 h******-1***

***Emission E******i***

**smearing, displacement**

**In absence of horizontal wind, mass balance for HCHO column ********HCHO****:**

**yield *****y******i***

**... ****but wind smears this local relationship between ********HCHO ****and *****E******i***** depending on the lifetime of the parent VOC with respect to HCHO production:**

**Local linear relationship**
**between HCHO and *****E***

**VOC source **

**Distance downwind**

******HCHO**

**Isoprene**

******-pinene**

**propane**

**100 km**

## SEASONAL VARIATION OF GOME HCHO COLUMNS OVER U.S. (9/96-8/97) IS DRIVEN BY ISOPRENE EMISSIONSCompare with HCHO columns from GEOS-CHEM CTM using Global Emission Inventory Activity (GEIA) emissions

**SEP**

**AUG**

**JUL**

**OCT**

**MAR**

**JUN**

**MAY**

**APR**

**   ****GOME             GEOS-CHEM (GEIA)           GOME               GEOS-CHEM (GEIA)**

***Abbot et al. [2003]***

## INVERTING HCHO COLUMN DATA FOR ISOPRENE EMISSION

**GOME slant columns (July 96)**

**GOME vertical columns (July 96)**

***E******ISOPRENE  ******=(1/S)*********HCHO****  **

**GOME **
**isoprene**
**emission **
**inventory**

**GEOS-CHEM**
**CTM**

**validation**
**With HCHO**
**surface air**
**observations**

**with GEIA**
**isoprene **
**emission**
**inventory**

**with GOME**
**isoprene**
**emission **
**inventory**

***Palmer et al. [2001, 2003]***

***E******ISOPRENE***

**HCHO column**

**non- isoprene contribution**

**Southeast U.S.**

**slope *****S***

## RECENT WORK

**Better quantify time-dependent HCHO yields from VOC oxidation using U. Leeds Master Chemical Mechanism (MCM);**
**Evaluate GEOS-CHEM relationship of HCHO column to isoprene emission, and GOME isoprene emission estimates, using in situ flux observations from PROPHET Michigan site;**
**Compare GOME to new-generation MEGAN isoprene emission inventory;**
**Test model simulation of  HCHO variability and vertical profiles using INTEX-A aircraft observations over North America;**
**Interpret GOME HCHO column observations over East Asia.**

## TIME-DEPENDENT HCHO YIELDS FROM VOC OXIDATION

***J. Stanton and M.J. Pilling (Leeds), P.I. Palmer (Harvard) ***

**Confirm high HCHO signal from isoprene with little smearing, **
**weak and smeared signal from terpenes; GEOS-CHEM yields may be**
**too low by 10-40% depending on NO****x**

**Box model simulations with state-of-science MCM v3.1 mechanism**

**methylbutenol**

## HCHO COLUMN vs. ISOPRENE EMISSION RELATIONSHIP

******HCHO****= *****S***** *****E******ISOPRENE***

**GEOS-CHEM model values of *****S*****  for 10-12 LT; regional and seasonal variation**

**Observed relationship of HCHO vs. isoprene emission flux measurements at PROPHET site in northern Michigan*****  *****(surface air HCHO measurement converted to column assuming 1 km scale height)**

**Jul 11-Aug 20 1998**
**10-12 LT**

**R = 0.44**
**Slope = 5.2x10****3**** s**

***P.I. Palmer (Harvard), S.N. Pressley and B. Lamb (WSU). A.-L. Sumner and P. Shepson (Purdue)***

**GEOS-CHEM slope may be ~30% too low**

## EVALUATING GOME ISOPRENE EMISSION ESTIMATES vs. PROPHET IN SITU FLUX MEASUREMENTS (2001)

**Also shown are local MEGAN isoperene emission inventory values**

***P.I. Palmer (Harvard), S.N. Pressley and B. Lamb (WSU), ***
***A. Guenther and C. Wiedinmyer (NCAR)***

## GOME vs. MEGAN ISOPRENE EMISSION INVENTORIES (2001)

** ****Good accord for seasonal variation, regional distribution of emissions;**
** ****GOME 10-34% higher than MEGAN depending on month, differences in hot spot locations**

***P.I. Palmer (Harvard), A. Guenther and C. Wiedinmyer (NCAR)***

## YEAR-TO-YEAR VARIABILITY OF GOME HCHO OVER SOUTHEAST U.S.

**GOME HCHO Column [10****16**** molec cm****-2****]**

- Southeast US average     32-38N; 265-280W

**YEAR-TO-YEAR VARIABILITY OF GOME HCHO OVER SOUTHEAST U.S.**

**Amplitude and phase are highly reproducible**

***P. I. Palmer (Harvard)***

## WHAT DRIVES GOME HCHO TEMPORAL VARIABILITY OVER SOUTHEAST U.S. DURING MAY-SEPTEMBER?

***P.I. Palmer (Harvard)***

**Monthly mean GOME HCHO vs. surface air temperature;**
**MEGAN parameterization shown as fitted curve **

## TESTING MODEL HCHO VARIABILITY AND AMFs USING ICARTT AIRCRAFT DATA (Jul-Aug 2004)

**0-10 km spirals and profiles during ICARTT**

**Observed (Fried)**
**Observed (Heikes)**
**GEOS-CHEM model**

***D.B. Millet (Harvard), ***
***A. Fried (NCAR) and  B.G. Heikes (URI)***

**Mean vertical**
**profiles**

** ****Exploit statistics on individual profiles to estimate model error on AMF;**
** ****Better understand factors driving HCHO variability**

## GOME HCHO COLUMNS OVER EAST ASIA (1997-2001)

**Relationship to VOC emissions far more complex than for N. America. Biomass burning, isoprene, anthropogenic VOCs, direct HCHO emission all contribute; need multivariate regression**

***T.-M. Fu (Harvard)***

## VOC CONTRIBUTIONS TO HCHO PRODUCTION IN CHINESE CITIES (JAN-FEB 2001)

**VOC CONTRIBUTIONS TO HCHO PRODUCTION ****IN CHINESE CITIES (JAN-FEB 2001)**

**NC**

**CC**

**WC**

**SC**

**Ethane****	****0.3 %****	****Benzene****	****0.4 %**
**Propane****	****0.3 %****	****Toluene****	****2.4 %**
**ALK4****	****5.1 %****	****Xylene****	****20.2 %**
**Ethene****	****19 %****	****Isoprene****	****8.2 %**
**PRPE****	****43 %**

***B. Barletta (UCI), T.-M. Fu (Harvard)***

**Vehicle-generated xylenes could make a large contribution to HCHO columns**