Modeling NHNO Over the San Joaquin Valley During the 2013 DISCOVER-AQ Campaign.

The San Joaquin Valley (SJV) of California experiences high concentrations of particulate matter NHNO during episodes of meteorological stagnation in winter. A rich data set of observations related to NHNO formation was acquired during multiple periods of elevated NHNO during the Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER-AQ) field campaign in SJV in January and February 2013. Here NHNO is simulated during the SJV DISCOVER-AQ study period with the Community Multiscale Air Quality (CMAQ) model, diagnostic model evaluation is performed using the DISCOVER-AQ data set, and integrated reaction rate analysis is used to quantify HNO production rates.

High-precision CO2 isotopologue spectrometer with a difference-frequency-generation laser source.

A precision laser spectrometer for the detection of CO(2) isotopes is reported. The spectrometer measures the fundamental absorption signatures of (13)C and (12)C isotopes in CO(2) at 4.32 microm using a tunable mid-IR laser source based on difference-frequency generation.

First demonstration of a high performance difference frequency spectrometer on airborne platforms.

We discuss the first airborne deployment and performance tests of a mid-IR difference frequency spectrometer system for highly sensitive measurements of formaldehyde. The laser system is based upon difference-frequency generation (DFG) at ~3.5 mum by mixing a DFB diode laser at 1562 nm and a distributed feedback (DFB) fiber laser at 1083 nm in a periodically poled LiNbO(3) (PPLN) crystal.