GEO-CAPE Emissions Working Group

What are the benefits of geostationary (GEO) measurements for constraining emissions and chemical processes?

Answer using pilot demonstrations of high resolution data from in-situ and remote sensing platforms, along with forward and inverse modeling analysis.

- assess an expanded suite of topics in 2013 (AOD and HCHO) - target specific questions related to emissions, beyond accounting

and beyond GEO lifetime

- compare value added of GEO relative to LEO

- utilize products from OSSE WGs

GEO-CAPE Emissions Working Group

I. Constraining anthropogenic emissions with satellite observations of HCHOSi-Wan Kim, NOAA/CU CIRES Greg Frost, NOAA/CU CIRESMichael Trainer, NOAARokjin Park, Seoul National University

• Simulate and evaluate HCHO in LA Basin for CalNex 2010 • Explore sensitivity of LEO and GEO HCHO columns to different emissions

inventories, including temporal variability• Parallel work using satellite and field observations of NO2 to constrain NOx

emissions in California• Explore formation of other secondary species (O3, glyoxal) using modeling

with field measurements and satellite data

WRF-Chem: Sensitivity to Emission InventoriesNO2 columns

HCHO columns

Glyoxal columnsO3 (PBL)

GEO-CAPE Emissions Working Group

II. Constraints on NO2 emissions and chemistryRon Cohen (UC Berkeley) Sensor array on 2km grid for CO2, NO2, O3, …

Nodes deployed on school rooftops

a) Use measurements from BEACON to characterize subgrid scale variability of NO2, CO and other gases

http://beacon.berkeley.edu/

Cohen-Emissions WGb) Use models and satellite observations to understand links between meteorology and NOx lifetime

GEO-CAPE Emissions Working Group

III. Constraints on sector-specific emissions contributions to CH4

Kevin Wecht, HarvardHelen Worden, NCARJohn Worden, JPLNicolas Bousserez, Andre Perkins, Daven Henze CU BoulderGreg Frost, NOAA/CU CIRESBob Chatfield, NASA AMES

OSSEs to evaluate the utility of GEO-CAPE methane observations for constraining North American emissions

-1.0 1.01.0 2.0

• Can we detect doubling of emissions from natural gas in the western US?• How do results compare to traditional LEO capabilities?

Step 1: Perturb model natural gas emissions by 2x in west.

Step 2: Sample model atmosphere with GEOCAPE obs. operator

Step 3: Assimilate pseudo-obs into GEOS-Chem adjoint inversion

GEOS-Chem CTM

GEOS-Chem Adjoint

GEOS-Chem CTM

0.750.0

200

1000

Pres

sure

[hpa

]

Rows of GEOCAPE averaging kernel matrix

0.1 hPa

954 hPa

Perturbed/prior emissions “Observed” enhancement

Observation Platform

Error reduction in perturbed region

Error reduction in North America

GEOCAPE 88 % 96 %

TES-like LEO 8 % 93 %

• Both GEOCAPE and LEO capture N.A. emissions.• Only GEOCAPE locates emissions within the perturbed region.

[ppb]

Emission error reduction achieved in OSSE

Address key questions using new inverse modeling diagnostics.

How many emissions have been constrained independently? Degree Of Freedom for Signal (DOFs)

To what extent are different CH4 sources (e.g., natural vs Oil&Gas) constrained independently from each other? Averaging kernel (or resolution) matrix

Example for toy CO2 inversion using pseudo GOSAT data:

0 0.33 0.67 1.00

Self-sensitivity ( )

DOFs=48.6

GOSAT CO2 monthly observations (2009/07)

GEO-CAPE Emissions Working Group

IV. Constraining aerosol sources with geostationary measurements

Jun Wang (UNL)Daven Henze (CUB)

Constraining aerosol sources with geostationary measurements

- radiances from TEMPO and GOES-R estimated for a variaty of different geostationary configurations (e.g., separating angle between the two instruments over North America)

- Utilize atmospheric samples from the OSSE group’s WRF-Chem 4 km nature runs.

- Aerosol WG activity: estimate the potential for constraining aerosol optical depth and possibly single scattering albedo.

- Emissions WG activity: extended to consider the potential for these radiances to constrain emissions using GEOS-Chem adjoint model

- Case studies targeting BC emissions from wildfires in the west during 2010/2011 will be targeted.

- Ability to constrain aerosol and aerosol precursor emissions using satellite AOD demonstrated in case studies (Wang et al., 2013; Xu et al., submitted).

- Global OSSE WG activity: extend to global scales, GEOS-5 nature run, constellation impacts.

GEO-CAPE Emissions Working Group

V. Constraints from geostationary observations on NH3 fluxes and associated PM2.5 concentrations

Karen Cady-Peirira (AER Inc.) Jesse Bash (US EPA), Juliet Zhu, Daven Henze (CU Boulder)

Constraints from geostationary observations on NH3 fluxes and associated PM2.5 concentrations

Motivation

• NH3 can impact PM2.5 concentrations by regulating NH4NO3

• Elevated aerosol nitrate concentrations linked to treatment of NH3 sources and sinks

• NH3 sources projected to increase, rivaling NO2 as source of reactive nitrogen deposition in the coming decades

• Progress hindered by uncertainty in NH3 fluxes

Nr tot

NOy

NHx

RCP8.564.52.6

Fabien Paulot et al., in prepWalker et al., 2012

measured [µg/m3]

GEO

S-Ch

em [µ

g/m

3 ]

US

CA

Paulot et al., 2012

Constraints from geostationary observations on NH3 fluxes and associated PM2.5 concentrations

Motivation

• NH3 can impact PM2.5 concentrations by regulating NH4NO3

• Elevated aerosol nitrate concentrations linked to treatment of NH3 sources and sinks

• NH3 sources projected to increase, rivaling NO2 as source of reactive nitrogen deposition in the coming decades

• Progress hindered by uncertainty in NH3 fluxes

GEO-CAPE Working Group Activities for 2012 / 2013

• Bidirectional air-surface exchange, fertilizer emissions, and diurnal variability of livestock emissions updated in GEOS-Chem and CMAQ

• Ensembles of model simulations run at 0.5 x 0.667 (GEOS-Chem) and 12 km (CMAQ) with different emissions process configuration.

• Model fields sampled according to LEO and GEO strategies; pseudo retrievals derived using TES algorithm

• Differences in pseudo observations show the potential for constraining NH3 emissions processes using GEO vs LEO remote sensing instruments.

TES overpass time

Current air quality models do not well represent the diurnal variability of livestock emissions (Jeong et al., submitted; Zhu et al., 2013).

Existing NH3 monitoring networks (2 week average) or remote sensing observations (twice a day) are insufficient to characterize NH3 diurnal variability.

Improved representation of NH3 diurnal variability impacts reactive nitrogen deposition and particulate formation. High bias in GEOS-Chem aerosol nitrate reduced by up to 1 ug/m3.

Workplan: CMAQ and GEOS-Chem & pseudo NH3 GEO-CAPE observations to assess the potential for geostationary measurements to constrain models’ diurnal emissions schemes.

2013 WG: diurnal variability of NH3 emissions

- what can we use from the regional and global OSSE groups?

- nature runs, averaging kernels

- to what extent do we focus on constraints on emissions vs chemical processing, deposition, etc.? can we be the chemistry / emissions WG?

- discovery about holes in models (e.g., VOC budget in SJ Valley)

- can emissions WG findings help other WGs? What outputs are needed?

- how do we adjust our activities to adapt to TEMPO / GCIRI future?

- does alignment / positioning / timing impact benefit of collocated measurements?

- CO / NOx, CO / VOC correlations, value high & contingent upon CO sensitivity

- what lasting knowledge will we have acquired regarding emissions (which are constantly changing) after the lifetime of GEO-CAPE instrument(s)?

- Can we be the chemistry / emissions WG?

- will we be prepared for inverse modeling capabilities at regional scale (4km) by 2020?

- ???

Topics for discussion

Extra slides

Model NOx lifetime vs. wind speed.

L Valin et al., GRL 2013

Riyadh

Low water, less OH, more NO2

High water, more OH, less NO2

Valin and Cohen in prep

H2O lifetimeshorterlonger

Valin and Cohen in prep

WRF-Chem NO2 columnsLos Angeles Basin

NO2 columns (1015 molec. cm-2)

LAX

PasadenaFontana

Irvine

Ontario

Riverside

14 LST

WRF-Chem: Diurnal variations of NO2, HCHO, Glyoxal, and O3

NO2 columns HCHO columns

Glyoxal columns O3 (PBL)

2012 WG: will geostationary observations help constraint NH3 bidirectional fluxes?

- NH3 retrievals were sampled from a CMAQ 4km simulated atmosphere

Geostationary retrievals of NH3 RVMR (ppb). Differences between each source model and base-case:

Bidi - Base Bidi-F - Base Bidi-F - Bidi

(x) location of TES global survey observations

Conclusion: A geostationary instrument could quantify differences in NH3 concentrations due to changes in the processes governing NH3 deposition and evasion. Existing remote sensing capabilities can not likely discern such differences.

- June 9th at 13:00, prior to peak difference in modeled NO3- on June 10th

- Radiative transfer model with applied noise used to get radiances- “TES like” error characteristics and sensitivities (i.e., Ak)

2012 WG: impacts if bidi fluxes of NH3 sources on NO3-

• Bidi: increased NO3 at CSN (10%) and IMPROVE (44%) sites• Bidi-F (+50% more fertilizer): increased NO3 at CSN (21%) and IMPROVE (19%) sites

Corresponding aerosol NO3- with different treatments of NH3 sources:

Comparison to observations:• All model cases underestimate NO3 concentrations

• Biases were ~10% less at CSN sites and ~20% less at IMPROVE sites in bidi case

CSN Base Bidi Bidi-F

07/01 07/04 07/07 07/10

•Geostationary NH3 retrievals would be instrumental in testing and evaluating NH3 air-surface exchange algorithms and emissions inventories.

• This would better inform policy makers’ assessments of current environmental conditions and identify mitigation strategies for:

• Conditions leading to nitrate PM episodes • Excessive nutrient depositions

Conclusions