# Presentation: 480524

## Measurements of HNO3 and HCl in the

**Measurements of HNO****3**** and HCl in the**
**Upper Troposphere and Lower Stratosphere**
**During AVE - Houston 2004**

- P.J. Popp, T.P. Marcy, R.S. Gao, L.A. Watts, R.H. Winkler, D.W. Fahey
- Aeronomy Laboratory
- National Oceanic and Atmospheric Administration
- Boulder, Colorado

**Notes:**
Wink’s photo credit   You can see our inlet pylon between the front and rear landing gear.

## HNO3 and HCl are detected through reactions with the SF5- reagent ion.

- HNO3 and HCl are detected through reactions with the SF5- reagent ion.

**The NOAA Chemical Ionization Mass Spectrometer (CIMS)**

- •

- •

- Front Inlet

- Bottom Inlet

- Both HNO3 and HCl are calibrated approximately once every hour during flight.
- Science-quality data can be obtained between 10 km and maximum WB-57F flight altitudes.

- •

- •

**Notes:**
Two channels with separate inlets (shown here on our inlet pylon) allow a measure of condensed species.  Data quality below 10 km limited by water vapor, which interferes with our ion-molecule reaction scheme.  We typically can’t report data when the ambient water vapor is greater than 100 ppmv.

## CIMS HNO3 and HCl Data Quality

|  | HNO3 | HCl |
| --- | --- | --- |
| Precision (1) | 15 pptv @ 50 pptv | 10 pptv @ 10 pptv |
| Accuracy | 30% + 15 pptv | 30% + 10 pptv |

- HNO3 and HCl data are reported at 1 Hz (3 data points per species per 10 s interval).

## AVE-Houston 2004 Flight Summary

**AVE-Houston 2004 Flight Summary**

| Flight Date | HNO3 Data
Available? | HCl Data
Available? | MLS
Track? | Comments |
| --- | --- | --- | --- | --- |
| 20041022 |  |  | - | Test flight, data not science quality |
| 20041026 |  |  | - | HNO3 on cirrus particles |
| 20041029 | * | * |  | Data lost during some periods |
| 20041031 | * | * |  | Data lost during some periods |
| 20041103 |  |  |  | HNO3 on cirrus particles |
| 20041105 | * | * |  |  |
| 20041107 |  |  |  |  |
| 20041109 |  |  |  | Bad zero gas, HNO3 data lost  |
| 20041110 |  |  |  |  |
| 20041112 |  |  |  | HNO3 on cirrus particles |

- * Preliminary data has been submitted to data archive.
- All final data should be submitted no later than March 31, 2005.

**Notes:**
Science-quality data was collected for at least one species on all science flights.  Preliminary data was submitted during the mission for 3 flights (asterisks).  Final data should be available on the data archive no later than March 31.  Who set the 20041110 flight plan?

## HNO3 Time Series Data (20041029)

**Notes:**
Two independent measurements track well, and give an indication of the signal-to-noise level we can achieve on an individual channel.

## HNO3 and HCl Vertical Profiles (20041029)

**Notes:**
Both HNO3 and HCl values increase at lower altitudes when at higher latitudes (purple points), indicating a lower tropopause (50-55 kft), whereas at lower latitudes (29° N), HNO3 and HCl don’t rise significantly until 55-60 kft.

## HNO3 and HCl Correlations With Ozone in the UT/LS

**HNO****3**** and HCl Correlations With Ozone in the UT/LS**
**(20041029)**

**Notes:**
HNO3/O3 correlation here (0.0027) is similar to that observed between 29-33 °N from Houston in September ‘99 during ACCENT (0.0023, Andy Neuman), and is higher than that observed in the subtropics (0.0012, Key West, CRYSTAL-FACE) and tropics (0.0010, pre-AVE, Costa Rica).  HCl correlation is ‘cleaner’ due to the lack of HCl chemistry in the troposphere.

## • The NOAA CIMS instrument can provide useful measurements of HNO3 and HCl in the UT/LS for Aura validation

- 	- vertical gradients
- 	- along track variability
- 	- correlation functions
- • The AVE-Houston CIMS dataset will be finalized by April 1, 2005
- • Need detailed CIMS/Aura intercomparisons to determine if validation strategy is effective

**Conclusions**