Abstract. Despite its clear importance, the monitoring of atmospheric ammonia,
including its sources, sinks, and links to the greater nitrogen cycle,
remains limited. Satellite data are helping to fill the gap in monitoring
from sporadic conventional ground- and aircraft-based observations to better
inform policymakers and assess the impact of any ammonia-related policies.
Presented is a description and survey that demonstrate the capabilities of
the Cross-track Infrared Sounder (CrIS) ammonia product for monitoring, air quality forecast model
evaluation, dry deposition estimates, and emission estimates from an
agricultural hotspot. For model evaluation, while there is a general
agreement in the spatial allocation of known major agricultural ammonia
hotspots across North America, the satellite observations show some high-latitude regions during peak forest
fire activity often have ammonia concentrations approaching those in
agricultural hotspots. The CrIS annual ammonia dry depositions in Canada
(excluding the territories) and the US have average and annual variability
values of ∼0.8±0.08 and
∼1.23±0.09 Tg N yr−1, respectively. These
satellite-derived dry depositions of reactive nitrogen from NH3 with NO2 show an annual ratio of NH3 compared to their sum (NH3+NO2) of ∼82 % and ∼55 % in Canada and the US, respectively. Furthermore, we show the use of CrIS satellite
observations to estimate annual and seasonal emissions near Lethbridge, Alberta,
Canada, a region dominated by high-emission
concentrated animal feeding operations (CAFOs); the satellite annual
emission estimate of 37.1±6.3 kt yr−1 is at least double the value
reported in current bottom-up emission inventories for this region.
A novel 3-D filtering method is presented for speckle reduction and detail preservation in automated 3-D ultrasound images. First, texture features of an image are analyzed by using the improved quadtree (QT) decomposition. Then, the optimal homogeneous and the obvious heterogeneous regions are selected from QT decomposition results. Finally, diffusion parameters and diffusion process are automatically decided based on the properties of these two selected regions. The computing time needed for 2-D speckle reduction is very short. However, the computing time required for 3-D speckle reduction is often hundreds of times longer than 2-D speckle reduction. This may limit its potential application in practice. Because this new filter can adaptively adjust the time step of iteration, the computation time is reduced effectively. Both synthetic and real 3-D ultrasound images are used to evaluate the proposed filter. It is shown that this filter is superior to other methods in both practicality and efficiency.
(2020) Expansion of a size disaggregation profile library for particulate matter emissions processing from three generic profiles to 36 source-type-specific profiles,
<p>Satellite data are helping to fill monitoring gaps in order to better inform decision makers and assess the impact of ammonia-related policies.&#160; Presented is an overview demonstrating the current capabilities of the ammonia (NH<sub>3</sub>) data product derived from the CrIS satellite instrument for monitoring, air quality forecast model evaluation, dry deposition estimates, and emissions estimates.&#160; This includes examples of daily, seasonal, and annual observations of CrIS ammonia that demonstrate the spatiotemporal variability of ammonia globally. These results further demonstrate the ability of CrIS to observe regional changes in ammonia concentrations, such as spring maximum values over agricultural regions from the fertilizing of crops.&#160; Also shown is the importance contribution of wildfires, especially in regions where there is little or no agriculture sources, such as the northern latitudes in North America during summer.&#160; Initial comparisons of CrIS NH<sub>3</sub> satellite observations with air quality model simulations show that while there is general agreement on the spatial distribution of the anthropogenic hotspots, some areas are markedly different.&#160; Some key findings are that dry deposition estimates of NH<sub>3</sub> and NO<sub>2</sub> from CrIS and the Ozone Monitoring Instrament (OMI), respectively, indicate that the NH<sub>3</sub> dominates over most regions across North America. Their 2013 annual ratio shows NH<sub>3</sub> accounting for ~82% and ~55 % of the combined reactive nitrogen dry deposition from these two species over Canada and the U.S.&#160; Furthermore, we show the use of CrIS satellite observations to estimate annual and seasonal emissions over Concentrated Animal Feeding Operations (CAFOs).&#160; These results are used to evaluate the seasonal and temporal emissions profiles used in bottom-up inventories over an agriculture hotspot, which are often underreported</p>
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