# Presentation: 201152

## Satellite Observations of Tropospheric Ammonia - Motivation and First Results

**Polluted profile from GEOS-Chem model used as initial guess**
**Doubled emissions to obtain new profile**
**Ran forward model over new profile to obtain simulated spectrum**
**Added noise**
**Performed retrieval**

**1. Motivation**
**Nitrogen in ammonia is deposited to Earth’s surface**
**Excess nitrogen leads to:**
**Nutrient imbalances**
**Change in ecosystem composition**
**Algal blooms**
**Hypoxia**
**Ammonium sulfate and ammonium nitrate form 10-20% of **_**fine particulate matter**_** (PM2.5)  in atmosphere over the US**
** ****Exceeds recommended threshold **(WHO, 2003)
** ****Excessive exposure to aerosol concentration is associated with : **
**Increased chances of cardiovascular disease **
**Inhibited lung development **
**Premature death **
- References (Burnett et al., 2000; Dominici et al., 2006; Gauderman et al., 2004; Pope , 2000; Pope et al., 2002)** **
**Fine particulates are also responsible for reduced visibility in national parks and scenic areas **(Malm et al., 2000)
**Point sources and short lifetime (less than 10 days) lead to high temporal and spatial variability**
**  ****In-situ measurement of ammonia are difficult and sparse **
** ****mostly confined to near surface**
**Physical and chemical processes governing ammonia emissions are  challenging to quantify**

**3. Proof of concept NH****3**** retrieval from TES**
**Simple scaling of NH****3**** profile to reduce residuals (Beer et al., 2008)**

- CHINA

- WEST COAST

-  Elevated amounts over Beijing, China, July 10, 2007
-  TES spectra can provide information on NH3 variability

**2. What TES can provide**

******TES data have been collected over most of the Earth’ surface since July 2004**
******TES can provide time series of NH****3**** mixing ratios almost anywhere on the globe**
******This dataset will provide a ****quantitative, global, long-term**** picture of NH****3**** spatial and temporal variability**
**First objective: provide monthly means for a year**
**Compare with output  from **_**regional**_** (e.g., CMAQ) and **_**global**_** models (e.g., GEOS-Chem)**
** ****Future objective:**
**Use intensive TES Special Observations to obtain NH3 concentrations over areas of high emission (e.g. North Carolina, Midwest)**
**Compare with in-situ measurements: **
****** ****More realistic spatial and temporal distribution of ammonia emissions**
****** ****Example: determine whether peak of NH****3**** emissions is:**
**In the spring (correlated with fertilizer application)**
**In the summer (higher temperatures lead to higher NH****3**** emissions from manure piles)**

**5. Sample retrieval: Doubling of NH****3**** emission**

**Retrieved-truth differences are within error bars**
**Retrieved profile is significantly different from *****a priori***
**TES retrieval provided added information**

| Mark W.Shephard, Karen E. Cady-Pereira, Vivienne H.Payne
AER, Inc. | Ming Luo, Curtis P. Rinsland, Reinhard Beer, Greg Osterman, Kevin Bowman
NASA-JPL | Daven Henze
Columbia University | Robert W.Pinder
US EPA-ORD  | Gary Lear
US EPA-CAMD | Shephard A. Clough
Clough Associates |
| --- | --- | --- | --- | --- | --- |

- Spectrum from TES pass over Beijing

**4. Retrieval Procedure**

-  **Optimal estimation approach. (Rodgers, 2000)**
** ****ill-posed problem (number of potential solutions)**
** ****nonlinear least square with constraints**

-  ***a priori***** estimate**
- GEOS-Chem profiles binned by surface NH3 amount

**6. Datasets for the Evaluation of TES NH****3**** Retrievals**

**GEOS-Chem Output for 2005**

**EPA NH****3**** Monitoring Network**
**Sampling began at most sites in October 2007**

-  ***a priori***** for TES scans over China**