We compare Tropospheric Emission Spectrometer (TES) version 2 (V002) nadir ozone profiles with ozonesonde profiles from the Intercontinental Chemical Transport Experiment Ozonesonde Network Study, the World Ozone and Ultraviolet Data Center, the Global Monitoring Division of the Earth System Research Laboratory, and the Southern Hemisphere Additional Ozonesonde archives. Approximately 1600 coincidences spanning 72.5°S–80.3°N from October 2004 to October 2006 are found. The TES averaging kernel and constraint are applied to the ozonesonde data to account for the TES measurement sensitivity and vertical resolution. TES sonde differences are examined in six latitude zones after excluding profiles with thick high clouds. Values for the bias and standard deviation are determined using correlations of mean values of TES ozone and sonde ozone in the upper troposphere (UT) and lower troposphere (LT). The UT biases range from 2.9 to 10.6 ppbv, and the LT biases range from 3.7 to 9.2 ppbv, excluding the Arctic and Antarctic LT where TES sensitivity is low. A similar approach is used to assess seasonal differences in the northern midlatitudes where the density and frequency of sonde measurements are greatest. These results are briefly compared to TES V001 ozone validation work which also used ozonesondes but was carried out prior to improvements in the radiometric calibration and ozone retrieval in V002. Overall, the large number of TES and sonde comparisons indicate a positive bias of approximately 3–10 ppbv for the TES V002 nadir ozone data set and have helped to identify areas of potential improvement for future retrieval versions.
Coordinated ozonesonde launches from the Intercontinental Transport Experiment (INTEX) Ozonesonde Network Study (IONS) (http://croc.gsfc.nasa.gov/intex/ions.html) in July‐August 2004 provided nearly 300 O3 profiles from eleven North American sites and the R/V Ronald H. Brown in the Gulf of Maine. With the IONS period dominated by low‐pressure conditions over northeastern North America (NENA), the free troposphere in that region was frequently enriched by stratospheric O3. Stratospheric O3 contributions to the NENA tropospheric O3 budget are computed through analyses of O3 laminae (Pierce and Grant, 1998; Teitelbaum et al., 1996), tracers (potential vorticity, water vapor), and trajectories. The lasting influence of stratospheric incursions into the troposphere is demonstrated, and the computed stratospheric contribution to tropospheric column O3 over the R/V Ronald H. Brown and six sites in Michigan, Virginia, Maryland, Rhode Island, and Nova Scotia, 23% ± 3%, is similar to summertime budgets derived from European O3 profiles (Collette and Ancellet, 2005). Analysis of potential vorticity, Wallops ozonesondes (37.9°N, 75.5°W), and Measurements of Ozone by Airbus In‐service Aircraft (MOZAIC) O3 profiles for NENA airports in June‐July‐August 1996–2004 shows that the stratospheric fraction in 2004 may be typical. Boundary layer O3 at Wallops and northeast U.S. sites during IONS also resembled O3 climatology (June‐July‐August 1996–2003). However, statistical classification of Wallops O3 profiles shows the frequency of profiles with background, nonpolluted boundary layer O3 was greater than normal during IONS.
We estimate the tropospheric column ozone using a forward trajectory model to increase the horizontal resolution of the Aura Microwave Limb Sounder (MLS) derived stratospheric column ozone. Subtracting the MLS stratospheric column from Ozone Monitoring Instrument total column measurements gives the trajectory enhanced tropospheric ozone residual (TTOR). Because of different tropopause definitions, we validate the basic residual technique by computing the 200‐hPa‐to‐surface column and comparing it to the same product from ozonesondes and Tropospheric Emission Spectrometer measurements. Comparisons show good agreement in the tropics and reasonable agreement at middle latitudes, but there is a persistent low bias in the TTOR that may be due to a slight high bias in MLS stratospheric column. With the improved stratospheric column resolution, we note a strong correlation of extratropical tropospheric ozone column anomalies with probable troposphere‐stratosphere exchange events or folds. The folds can be identified by their colocation with strong horizontal tropopause gradients. TTOR anomalies due to folds may be mistaken for pollution events since folds often occur in the Atlantic and Pacific pollution corridors. We also compare the 200‐hPa‐to‐surface column with Global Modeling Initiative chemical model estimates of the same quantity. While the tropical comparisons are good, we note that chemical model variations in 200‐hPa‐to‐surface column at middle latitudes are much smaller than seen in the TTOR.
Abstract. The Maritime Aerosol Network (MAN) has been collecting data over the oceans since November 2006. Over 80 cruises were completed through early 2010 with deployments continuing. Measurement areas included various parts of the Atlantic Ocean, the Northern and Southern Pacific Ocean, the South Indian Ocean, the Southern Ocean, the Arctic Ocean and inland seas. MAN deploys Microtops handheld sunphotometers and utilizes a calibration procedure and data processing traceable to AERONET. Data collection included areas that previously had no aerosol optical depth (AOD) coverage at all, particularly vast areas of the Southern Ocean. The MAN data archive provides a valuable resource for aerosol studies in maritime environments. In the current paper we present results of AOD measurements over the oceans, and make a comparison with satellite AOD retrievals and model simulations.
The CWRF is developed as a climate extension of the Weather Research and Forecasting model (WRF) by incorporating numerous improvements in the representation of physical processes and integration of external (top, surface, lateral) forcings that are crucial to climate scales, including interactions between land, atmosphere, and ocean; convection and microphysics; and cloud, aerosol, and radiation; and system consistency throughout all process modules. This extension inherits all WRF functionalities for numerical weather prediction while enhancing the capability for climate modeling. As such, CWRF can be applied seamlessly to weather forecast and climate prediction. The CWRF is built with a comprehensive ensemble of alternative parameterization schemes for each of the key physical processes, including surface (land, ocean), planetary boundary layer, cumulus (deep, shallow), microphysics, cloud, aerosol, and radiation, and their interactions. This facilitates the use of an optimized physics ensemble approach to improve weather or climate prediction along with a reliable uncertainty estimate. The CWRF also emphasizes the societal service capability to provide impactrelevant information by coupling with detailed models of terrestrial hydrology, coastal ocean, crop growth, air quality, and a recently expanded interactive water quality and ecosystem model. This study provides a general CWRF description and basic skill evaluation based on a continuous integration for the period 1979– 2009 as compared with that of WRF, using a 30-km grid spacing over a domain that includes the contiguous United States plus southern Canada and northern Mexico. In addition to advantages of greater application capability, CWRF improves performance in radiation and terrestrial hydrology over WRF and other regional models. Precipitation simulation, however, remains a challenge for all of the tested models.
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