GMAC LAG Poster 2013

Data display (poster format

Overview Of The NOAA/ESRL Federated Aerosol Network

To estimate global aerosol radiative forcing, measurements of aerosol optical properties are made by the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ESRL)’s Global Monitoring Division (GMD) and their collaborators at 30 monitoring locations around the world. Many of the sites are located in regions influenced by specific aerosol types (Asian and Saharan desert dust, Asian pollution, biomass burning, etc.). This network of monitoring stations is a shared endeavor of NOAA and many collaborating organizations, including the World Meteorological Organization (WMO)’s Global Atmosphere Watch (GAW) program, the U.S. Department of Energy (DOE), several U.S. and foreign universities, and foreign science organizations. The result is a long-term cooperative program making atmospheric measurements that are directly comparable with those from all the other network stations and with shared data access. The protocols and software developed to support the program facilitate participation in GAW’s atmospheric observation strategy, and the sites in the NOAA/ESRL network make up a substantial subset of the GAW aerosol observations. This paper describes the history of the NOAA/ESRL Federated Aerosol Network, details about measurements and operations, and some recent findings from the network measurements

A Multi-Year Study Of Lower Tropospheric Aerosol Variability And Systematic Relationships From Four North American Regions

Hourly averaged aerosol optical properties (AOPs) measured over the years 2010–2013 at four continental North American NOAA Earth System Research Laboratory (NOAA/ESRL) cooperative aerosol network sites – Southern Great Plains near Lamont, OK (SGP), Bondville, IL (BND), Appalachian State University in Boone, NC (APP), and Egbert, Ontario, Canada (EGB) are analyzed. Aerosol optical properties measured over 1996–2009 at BND and 1997–2009 at SGP are also presented. The aerosol sources and types in the four regions differ enough so as to collectively represent rural, anthropogenically perturbed air conditions over much of eastern continental North America. Temporal AOP variability on monthly, weekly, and diurnal timescales is presented for each site. Differences in annually averaged AOPs and those for individual months at the four sites are used to examine regional AOP variability. Temporal and regional variability are placed in the context of reported aerosol chemistry at the sites, meteorological measurements (wind direction, temperature), and reported regional mixing layer heights. Basic trend analysis is conducted for selected AOPs at the long-term sites (BND and SGP). Systematic relationships among AOPs are also presented

CAN-DOO: Climate Action Network Through Direct Observations And Outreach

2011 Fall Southeast Regional Space Grant Meeting, September 9, 2011. The urgency of climate change demands a greater understanding of our climate system, not only by the leaders of today, but by the scientists, policy makers, and citizens of tomorrow. Unfortunately, a large segment of the population currently possesses inadequate knowledge of climate science. In direct response to a need for greater scientific literacy with respect to climate science, researchers from Appalachian State University's Appalachian Atmospheric Interdisciplinary Research (AppalAIR) group, with support from NASA, have developed CAN-DOO: the Climate Action Network through Direct Observations and Outreach. CAN-DOO addresses climate science literacy by 1) Developing the infrastructure for sustaining and expanding public outreach through long-term climate measurements capable of complementing existing NASA measurements, 2) Enhancing public awareness of climate science and NASA's role in advancing our understanding of the Earth System, and 3) Introducing Science, Technology, Engineering, and Mathematics principles to homeschooled, public school, and Appalachian State University students through applied climate science activities. Project partners include the Grandfather Mountain Stewardship Foundation, Pisgah Astronomical Research Institute, and local elementary schools. In partnership with Grandfather Mountain, climate science awareness is promoted through citizen science activities, interactive public displays, and staff training. CAN-DOO engages students by involving them in the entire scientific investigative process as applied to climate science. We introduce local elementary and middle school students, homeschooled students throughout North Carolina, and undergraduate students in a new Global Climate Change course and select other courses at Appalachian State University to instrument assembly, measurement techniques, data collection, hypothesis testing, and drawing conclusions. Results are placed in the proper context via comparisons with other student data products, local research-grade measurements, and NASA measurements. Several educational modules have been developed that address specific topics in climate science. The modules are scalable and have been successfully implemented at levels ranging from 2nd grade through first-year graduate as well as with citizen science groups. They also can be applied in user-desired segments to a variety of Earth Science units. In this paper, we will introduce the project activities and present results from the first year of observations and outreach, with a special emphasis on two of the developed modules, the surface energy balance and aerosol optical depth module

An Evaluation Of MODIS-Retrieved Aerosol Optical Depth Over A Mountainous AERONET Site In The Southeastern US

The literature shows that aerosol optical depth (AOD) derived from the MODIS Collection 5 (C5) dark target algorithm has been extensively validated by spatiotemporal collocation with AERONET sites on both global and regional scales. Although generally comparing well over the eastern US region, poor performance over mountains in other regions indicate the need to evaluate the MODIS product over a mountain site. This study compares MODIS C5 AOD at 550nm to AOD measured at the Appalachian State University AERONET site in Boone, NC over 30 months between August 2010 and September 2013. For the combined Aqua and Terra datasets, although more than 70% of the 500 MODIS AOD measurements agree with collocated AERONET AOD to within error envelope of ± (0.05 + 15%), MODIS tends to have a low bias (0.02–0.03). The agreement between MODIS and AERONET AOD does not depend on MODIS quality assurance confidence (QAC) value. However, when stratified by satellite, MODIS-Terra data does not perform as well as Aqua, with especially poor correlation (r = 0.39) for low aerosol loading conditions (AERONET AOD less than 0.15). Linear regressions between Terra and AERONET possess statistically-different slopes for AOD < 0.15 and AOD = 0.15. AERONET AOD measured only during MODIS overpass hours is highly correlated with daily-averaged AERONET AOD. MODIS monthly-averaged AOD also tracks that of AERONET over the study period. These results indicate that MODIS is sensitive to the day-to-day variability, as well as the annual cycle of AOD over the Appalachian State AERONET site. The complex topography and high seasonality in AOD and vegetation indices allow us to specifically evaluate MODIS dark target algorithm surface albedo and aerosol model assumptions at a regionally-representative SE US mountain site

A Characterization Of Volatile Organic Compounds And Secondary Organic Aerosol At A Mountain Site In The Southeastern United States

Mean temperature anomalies in the Southeastern United States (SEUS) over the past century have reflected regional cooling hypothesized to be a result of an enhancement of warm season aerosol optical thickness caused by the oxidation of biogenic volatile organic compounds (VOCs). Aerosol and gas-phase VOC measurements were made at the Appalachian Atmospheric Interdisciplinary Research (AppalAIR) site in the southern Appalachian mountains of North Carolina during the summer of 2013 in an effort to characterize warm season chemistry. Organic aerosol (OA) chemistry was characterized through a positive matrix factorization analysis resolving a low-volatility, semi-volatile, and isoprene oxidation factor contributing 34±15, 24±12, and 42±17 %, respectively to the total observed OA. Volatile organic compound characterization described chemistry that was typical of rural background levels with periods of elevated hydrocarbon and urban tracer loading that varied with synoptic flow. Chemical, meteorological, and aerosol optical property data suggested that measurements made at the AppalAIR site are representative of background atmospheric chemistry in the SEUS. Annual background secondary organic aerosol (SOA) production in the SEUS was estimated to be 0.15–0.50 GgC yr-1. Estimates of total and background SOA from this study provide evidence that the SEUS is a region of global significance in the context of global SOA budgets, and can be useful in understanding the extent of anthropogenic enhancement of summertime SOA compared to background levels

Aerosol-Precipitation Interactions In The Southern Appalachian Mountains

There are many uncertainties associated with aerosol-precipitation interactions, particularly in mountain regions where a variety of processes at different spatial scales influence precipitation patterns. Aerosol-precipitation linkages were examined in the southern Appalachian Mountains, guided by the following research questions: (1) how do aerosol properties observed during precipitation events vary by season (e.g., summer vs. winter) and synoptic event type (e.g., frontal vs. non-frontal); and (2) what influence does air mass source region have on aerosol properties? Precipitation events were identified based on regional precipitation data and classified using a synoptic classification scheme developed for this study. Hourly aerosol data were collected at the Appalachian Atmospheric Interdisciplinary Research (AppalAIR) facility at Appalachian State University in Boone, NC (1110 m a.s.l., 36.215, 81.680). Backward air trajectories provided information on upstream atmospheric characteristics and source regions. During the warm season (June to September), greater aerosol loading dominated by larger particles was observed, while cool season (November to April) precipitation events exhibited overall lower aerosol loading with an apparent influence from biomass burning particles. Aerosol-induced precipitation enhancement may have been detected in each season, particularly during warm season non-frontal precipitation

Measurement-Based Climatology Of Aerosol Direct Radiative Effect, Its Sensitivities, And Uncertainties From A Background Southeast US Site

Aerosol optical properties measured at Appalachian State University’s co-located NASA AERONET and NOAA ESRL aerosol network monitoring sites over a nearly four-year period (June 2012–Feb 2016) are used, along with satellite-based surface reflectance measurements, to study the seasonal variability of diurnally averaged clear sky aerosol direct radiative effect (DRE) and radiative efficiency (RE) at the top-of-atmosphere (TOA) and at the surface. Aerosol chemistry and loading at the Appalachian State site are likely representative of the background southeast US (SE US), home to high summertime aerosol loading and one of only a few regions not to have warmed during the 20th century. This study is the first multi-year “ground truth” DRE study in the SE US, using aerosol network data products that are often used to validate satellite-based aerosol retrievals. The study is also the first in the SE US to quantify DRE uncertainties and sensitivities to aerosol optical properties and surface reflectance, including their seasonal dependence

What Do 10 Years Of Atmospheric Aerosol Measurements From The NOAA And NASA Aerosol Monitoring Sites At App Tell Us About The Effect Of Changing SE U.S. Air Quality On Regional Solar Radiation And Climate? (Abstract only)

The effects of atmospheric aerosols (haze, dust, smoke) on solar radiation and clouds represent the largest uncertainties in climate models used to predict future temperatures, according to the most recent Intergovernmental Panel on Climate Change (IPCC) assessment. The southeastern U.S. is home to high summertime haze levels, which may have contributed to lack of regional warming during 20th century. Improvements in U.S. air quality in the past 2-3 decades may reduce the cooling effect of aerosols in SE U.S. but there is a scarcity of long-term aerosol measurements needed to evaluate climate models. Appalachian State University (APP) is home to one of the two most comprehensive aerosol monitoring facilities in the U.S. and the only comparable facility relying completely on students to assist the project investigator. Over 50 students have contributed to the long term (10 year) aerosol datasets from the NOAA and NASA network sites at APP, which will be used by the Aerosols Working Group as part of the upcoming IPCC assessment. Aerosol loading has decreased significantly over the 10 years of measurements at APP, leading to a smaller aerosol cooling effect which is most pronounced during summer months. The decreases in light absorption are likely influenced by reductions in diesel emissions. Reductions in aerosol light scattering are consistent with reductions in SO2 emissions by coal-burning power plants in eastern U.S. Long-term aerosol datasets from APP will be presented, along with results from the first measurement-based study of aerosol direct radiative effect in SE U.S. (Sherman and McComiskey)