scholarly journals Satellite- and ground-based CO total column observations over 2010 Russian fires: accuracy of top-down estimates based on thermal IR satellite data

2011 ◽  
Vol 11 (15) ◽  
pp. 7925-7942 ◽  
Author(s):  
L. N. Yurganov ◽  
V. Rakitin ◽  
A. Dzhola ◽  
T. August ◽  
E. Fokeeva ◽  
...  
Keyword(s):  
Balance Model ◽  
Top Down ◽  
Fire Event ◽  
Mixing Ratios ◽  
Central Russia ◽  
Simple Mass ◽  
Peat Fires ◽  
Three Space ◽  
Total Column ◽  
Moscow Area

Abstract. CO total column data are presented from three space sounders and two ground-based spectrometers in Moscow and its suburbs during the forest and peat fires that occurred in Central Russia in July–August 2010. Also presented are ground-based in situ CO measurements. The Moscow area was strongly impacted by the CO plume from these fires. Concurrent satellite- and ground-based observations were used to quantify the errors of CO top-down emission estimates. On certain days, CO total columns retrieved from the data of the space-based sounders were 2–3 times less than those obtained from the ground-based sun-tracking spectrometers. The depth of the polluted layer over Moscow was estimated using total column measurements compared with CO volume mixing ratios in the surface layer and on the TV tower and found to be around 360 m. The missing CO that is the average difference between the CO total column accurately determined by the ground spectrometers and that retrieved by AIRS, MOPITT, and IASI was determined for the Moscow area between 1.6 and 3.3 × 1018 molec cm−2. These values were extrapolated onto the entire plume; subsequently, the CO burden (total mass) over Russia during the fire event was corrected. A top-down estimate of the total emitted CO, obtained by a simple mass balance model increased by 40–100 % for different sensors due to this correction. Final assessments of total CO emitted by Russian wildfires obtained from different sounders are between 34 and 40 Tg CO during July–August 2010.

scholarly journals Satellite- and ground-based CO total column observations over 2010 Russian fires: accuracy of top-down estimates based on thermal IR satellite data.

2011 ◽  
Vol 11 (4) ◽  
pp. 12207-12250 ◽  
Author(s):  
L. Yurganov ◽  
V. Rakitin ◽  
A. Dzhola ◽  
T. August ◽  
E. Fokeeva ◽  
...  
Keyword(s):  
Balance Model ◽  
Top Down ◽  
Fire Event ◽  
Mixing Ratios ◽  
Central Russia ◽  
Abstract Data ◽  
Simple Mass ◽  
Peat Fires ◽  
Total Column ◽  
Moscow Area

Abstract. Data are presented from three space sounders and two ground-based spectrometers in Moscow and its suburbs during the forest and peat fires that occurred in Central Russia in July–August 2010. The Moscow area was strongly impacted by the CO plume from these fires. Concurrent satellite- and ground-based observations were used to quantify the errors of CO top-down emission estimates. On certain days, CO total columns retrieved from the data of the space-based sounders were 2–3 times less than those obtained from the ground-based sun-tracking spectrometers. The depth of the polluted layer over Moscow was estimated using total column measurements compared with CO volume mixing ratios in the surface layer and on the TV tower and found to be between 180 and 360 m. The missing CO that is the average difference between the CO total column accurately determined by the ground spectrometer and that retrieved by MOPITT and AIRS, was determined for the Moscow area as ∼3 E18 molec cm−2. This value was extrapolated onto the entire plume; subsequently, the CO burden (total mass) over Russia during the fire event was corrected. A top-down estimate of the total emitted CO, obtained by a simple mass balance model increased by 80%–100% due to this correction (up to 40 Tg).

scholarly journals Observation and analysis of spatio-temporal characteristics of surface ozone and carbon monoxide at multiple sites in the Kathmandu Valley, Nepal

2017 ◽  
Author(s):  
Khadak Singh Mahata ◽  
Maheswar Rupakheti ◽  
Arnico Kumar Panday ◽  
Piyush Bhardwaj ◽  
Manish Naja ◽  
...  
Keyword(s):  
Air Pollution ◽  
Forest Fires ◽  
Mountain Pass ◽  
Kathmandu Valley ◽  
Emission Flux ◽  
Mixing Ratio ◽  
Top Down ◽  
Monsoon Period ◽  
Temporal Characteristics ◽  
Mixing Ratios

Abstract. Residents of the Kathmandu Valley experience severe particulate and gaseous air pollution throughout most of the year, even during much of the rainy season. The knowledge base for understanding the air pollution in the Kathmandu Valley was previously very limited, but is improving rapidly due to several field measurement studies conducted in the last few years. Thus far, most analyses of observations in the Kathmandu Valley have been limited to short periods of time at single locations. This study extends on the past studies by examining the spatial and temporal characteristics of two important gaseous air pollutant (CO and O3) based on simultaneous observations over a longer period at five locations within the valley and on its rim, including a supersite (at Bode in the valley center, 1345 m above sea level) and four satellite sites (at Paknajol, 1380 m asl in the Kathmandu city center, at Bhimdhunga (1522 m asl), a mountain pass on the valley's western rim, at Nagarkot (1901 m asl), another mountain pass on the eastern rim, and Naikhandi, near the valley's only river outlet). CO and O3 mixing ratios were monitored from January to July 2013, along with other gases and aerosol particles by instruments deployed at the Bode supersite during the international air pollution measurement campaign SusKat-ABC (Sustainable Atmosphere for the Kathmandu Valley – endorsed by the Atmospheric Brown Clouds program of UNEP). The O3 monitoring at Bode, Paknajol and Nagarkot as well as the CO monitoring at Bode were extended beyond July 2013 to investigate their variability over a complete annual cycle. Higher CO mixing ratios were found at Bode than at the outskirt sites (Bhimdhunga, Naikhandi and Nagarkot), and all sites except Nagarkot showed distinct diurnal cycles of CO mixing ratio with morning peaks and daytime lows. Seasonally, CO was higher during the pre-monsoon and winter seasons, especially due to the emissions from brick kiln industries, which only operate during this period, as well as increased domestic heating during winter, and regional forest fires and agro-residue burning. It was lower during the monsoon due to rainfall, which reduces open burning activities within the valley and in the surrounding regions, and thus reduces the sources of CO. The meteorology of the valley also played a key role in determining the CO mixing ratios. Furthermore, there was evidence of some influence of pollution from the greater region around the valley. A top-down estimate of the CO emission flux was made by using the CO mixing ratio and mixing layer height (MLH) measured at Bode. The estimated annual CO flux at Bode was 4.92 μg m−2 s−1, which is 2–14 times higher than that in widely used emission inventory databases (EDGAR HTAP, REAS and INTEX-B). This difference in CO flux between Bode and other emission databases likely arises from large uncertainties in both the top-down and bottom-up approaches to estimating the emission flux. The O3 mixing ratio was found to be highest during the pre-monsoon season at all sites, while the timing of the seasonal minimum varied across the sites. The daily maximum 8 hour average O3 exceeded the WHO recommended guideline of 50 ppb on more days at the hilltop station of Nagarkot (159/357 days) than at the urban valley bottom sites of Paknajol (132/354 days) and Bode (102/353 days), presumably due to the influence of free-tropospheric air at the high-altitude site, as well as to titration of O3 by fresh NOx emissions near the urban sites. More than 78 % of the exceedance days were during the pre-monsoon period at all sites. This was due to both favorable meteorological conditions as well as contributions of precursors from regional sources such as forest fires and agro-residue burning. The high O3 mixing ratio observed during the pre-monsoon period is of a high concern for human health and ecosystems, including agroecosystems in the Kathmandu Valley and surrounding regions.

scholarly journals Characterizing ozone throughout the atmospheric column over the tropical Andes from in situ and remote sensing observations

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
María Cazorla ◽  
René Parra ◽  
Edgar Herrera ◽  
Francisco Raimundo da Silva
Keyword(s):  
Boundary Layer ◽  
Atmospheric Ozone ◽  
Tropical Andes ◽  
Total Column Ozone ◽  
Study Region ◽  
Boundary Layer Height ◽  
Mixing Ratios ◽  
The Andes ◽  
Column Ozone ◽  
Total Column

In this study, we characterize atmospheric ozone over the tropical Andes in the boundary layer, the free troposphere, and the stratosphere; we quantify each contribution to total column ozone, and we evaluate the performance of the multi-sensor reanalysis (MSR2) in the region. Thus, we present data taken in Ecuador and Peru (2014–2019). The contribution from the surface was determined by integrating ozone concentrations measured in Quito and Cuenca (Ecuador) up to boundary layer height. In addition, tropospheric and stratospheric column ozone were quantified from ozone soundings (38) launched from Quito during the study time period. Profiles were compared against soundings at Natal (SHADOZ network) for being the closest observational reference with sufficient data in 2014–2019. Data were also compared against stratospheric mixing ratios from the Aura Microwave Limb Sounder (Aura MLS). Findings demonstrate that the stratospheric component of total column ozone over the Andes (225.2 ± 8.9 Dobson Units [DU]) is at similar levels as those observed at Natal (223.3 ± 8.6 DU), and observations are comparable to Aura MLS data. In contrast, the tropospheric contribution is lower over the Andes (20.2 ± 4.3 DU) when compared to Natal (35.4 ± 6.4 DU) due to a less deep and cleaner troposphere. From sounding extrapolation of Quito profiles down to sea level, we determined that altitude deducts about 5–7 DU from the total column, which coincides with a 3%–4% overestimation of the MSR2 over Quito and Marcapomacocha (Peru). In addition, when MSR2 data are compared along a transect that crosses from the Amazon over Quito, the Ecuadorian coast side, and into the Pacific, observations are not significantly different among the three first locations. Results point to coarse reanalysis resolution not being suitable to resolve the formidable altitude transition imposed by the Andes mountain chain. This work advances our knowledge of atmospheric ozone over the study region and provides a robust time series of upper air measurements for future evaluations of satellite and reanalysis products.

scholarly journals Top-down estimation of carbon monoxide emissions from the Mexico Megacity based on FTIR measurements from ground and space

2012 ◽  
Vol 12 (11) ◽  
pp. 29915-29965 ◽  
Author(s):  
W. Stremme ◽  
M. Grutter ◽  
C. Rivera ◽  
A. Bezanilla ◽  
A. R. Garcia ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Spatial Distribution ◽  
Mexico City ◽  
Emission Flux ◽  
Top Down ◽  
Solar Absorption ◽  
Surface Emission ◽  
The Difference ◽  
Anthropogenic Pollutant ◽  
Total Column

Abstract. Continuous carbon monoxide (CO) total column densities above the UNAM campus in Mexico City have been derived from solar absorption infrared spectroscopic measurements since October 2007. Its diurnal evolution is used in the present study in conjunction with other ground-based and satellite data to develop a top-down emission estimate of the annual CO emission of the Mexico City Metropolitan Area (MCMA). The growth-rate of the total column around noon under low ventilation conditions is calculated and allows us to derive the average surface emission-flux at UNAM, while similar measurements taken at the edge of the MCMA in Tecámac provides information on background CO levels in the Mexico basin. Based on 3 yr of measurements, CO column measurements from the IASI satellite instrument are used to reconstruct the spatial distribution of this anthropogenic pollutant over the MCMA. The agreement between the measured columns of the satellite and ground-based measurements is excellent, particularly when a comparison strategy based on time-displaced air masses is used. The annual emission of the Mexico Megacity is estimated to be (2.15 ± 0.5) Tg yr−1 for the year 2008, while the official inventory for that year reported 1.6 Tg yr−1. The difference is slightly higher than the conservative uncertainty estimated in this work suggesting that the emission might be underestimated by the conventional bottom-up method. A larger discrepancy is found in the spatial distribution of the emissions, when comparing the emission flux over UNAM (derived from the ground-based measurement) with that of the inventory integrated over a representative area. The methodology presented here represents a new and useful strategy to evaluate the contribution of megacities to the global anthropogenic gas emissions. Additionally, three different strategies to compare ground and space-based measurements above an inhomogeneous and strongly contaminated area like Mexico City are presented and discussed.

Generation and Enforcement of Process-Driven Manufacturability Constraints: A Survey of Methods and Perspectives for Product Design

2021 ◽  
pp. 1-33
Author(s):  
Albert Patterson ◽  
Yong Hoon Lee ◽  
James T. Allison
Keyword(s):  
General Solution ◽  
Design For Manufacturing ◽  
Top Down ◽  
Specific Process ◽  
Micro Scale ◽  
Component Design ◽  
Macro Scale ◽  
Simple Mass ◽  
Common Problems ◽  
Scale Design

Abstract Design-for-manufacturing (DFM) concepts have traditionally focused on design simplification; this is highly effective for relatively simple, mass-produced products, but tends to be too restrictive for more complex designs. Effort in recent decades has focused on creating methods for generating and imposing specific, process-derived technical manufacturability constraints for some common problems. This paper presents an overview of the problem and its design implications, a discussion of the nature of the manufacturability constraints, and a survey of the existing approaches and methods for generating/enforcing the minimally-restrictive manufacturability constraints within several design domains. Five major design perspectives or viewpoints were included in the study, including the system design (top-down), product/component design (bottom-up), the manufacturing process-dominant case (product/component design under a specific process), the part-redesign perspective, and sustainability perspective. Manufacturability constraints within four design levels or scales were explored as well, ranging from macro-scale to sub-micro-scale design. Very little previous work was found in many areas, but it is clear from the existing literature that the problem and a general solution to it are very important to explore further in future DFM efforts.

scholarly journals Recent variations of calving glaciers in Patagonia, South America, revealed by ground surveys, satellite-data analyses and numerical experiments

1995 ◽  
Vol 21 ◽  
pp. 297-303 ◽  
Author(s):  
Renji Naruse ◽  
Masamu Aniya ◽  
Pedro Skvarca ◽  
Gino Gasassa
Keyword(s):  
South America ◽  
Mass Balance ◽  
Numerical Experiments ◽  
Satellite Images ◽  
Balance Model ◽  
Equilibrium Line Altitude ◽  
Simple Mass ◽  
Surface Profiles ◽  
The Difference ◽  
Altitudinal Distributions

Large retreats were revealed for most glaciers in Patagonia, South America, by analyzing satellite images and air photographs. For example, Glaciar O’Higgins retreated 13 km during 41 years from 1945 to 1986 and Glaciar Upsala retreated about 3 km between 1968 and 1990. During the 41 years former period, however, the southern tongue of Glaciar Pio XI advanced by up to 8.5 km and Glaciar Moreno remained almost in a steady state. Considerable ice-thinning rates, from 3.0 to 11 ma−1, were measured by surveying surface profiles in the ablation areas of Tyndall and Upsala glaciers, respectively, during the period from 1985 (or 1990) to 1993. The ice thickness of Glaciar Moreno, however, has changed very little. Numerical experiments using a simple mass-balance model show that a 100 m rise in the equilibrium-line altitude due to climatic change would result in about a 200–350 m rise in the frontal altitude at Glaciar Upsala corresponding to a retreat of 5–8 km, while it would cause only about a 70–100 m rise at Glaciar Moreno. The large difference between these two neighbouring glaciers results from the difference in contributions of the calving amount to the total mass balance, as well as the difference in the altitudinal distributions of drainage areas.

Overview of the Development and Enforcement of Process-Driven Manufacturability Constraints in Product Design

2019 ◽  
Author(s):  
Albert E. Patterson ◽  
Yong Hoon Lee ◽  
James T. Allison
Keyword(s):  
Product Design ◽  
Design Automation ◽  
Design For Manufacturing ◽  
Top Down ◽  
Specific Process ◽  
Micro Scale ◽  
Macro Scale ◽  
Simple Mass ◽  
Common Problems ◽  
Scale Design

Abstract Design-for-manufacturing (DFM) concepts have traditionally focused on design simplification; this is highly effective for relatively simple, mass-produced products, but tends to be too restrictive for more complex designs. Effort in recent decades has focused on creating methods for generating and imposing specific, process-derived technical manufacturability constraints for some common problems. This paper presents an overview of the problem and its design implications, a discussion of the nature of the manufacturability constraints, and a survey of the existing approaches and methods for generating/enforcing the minimally restrictive manufacturability constraints within several design domains. Four major design perspectives were included in the study, including the system design (top-down), the product design (bottom-up), the manufacturing process-dominant approach (specific process required), and the part-redesign approach. Manufacturability constraints within four design levels were explored as well, ranging from macro-scale to sub-micro-scale design. Very little previous work was found in many areas but it is clear from the existing literature that the problem and a general solution to it are very important to explore further in future DFM and design automation work.

scholarly journals Southern hemispheric halon trends and global halon emissions, 1978–2011

2013 ◽  
Vol 13 (11) ◽  
pp. 5551-5565 ◽  
Author(s):  
M. J. Newland ◽  
C. E. Reeves ◽  
D. E. Oram ◽  
J. C. Laube ◽  
W. T. Sturges ◽  
...  
Keyword(s):  
Steady State ◽  
Atmospheric Model ◽  
Production Data ◽  
Two Dimensional ◽  
Top Down ◽  
East Anglia ◽  
Mixing Ratios ◽  
The Past ◽  
Alternative Set ◽  
Cape Grim

Abstract. The atmospheric records of four halons, H-1211 (CBrClF2), H-1301 (CBrF3), H-2402 (CBrF2CBrF2) and H-1202 (CBr2F2), measured from air collected at Cape Grim, Tasmania, between 1978 and 2011, are reported. Mixing ratios of H-1211, H-2402 and H-1202 began to decline in the early to mid-2000s, but those of H-1301 continue to increase up to mid-2011. These trends are compared to those reported by NOAA (National Oceanic and Atmospheric Administration) and AGAGE (Advanced Global Atmospheric Experiment). The observations suggest that the contribution of the halons to total tropospheric bromine at Cape Grim has begun to decline from a peak in 2008 of about 8.1 ppt. An extrapolation of halon mixing ratios to 2060, based on reported banks and predicted release factors, shows this decline becoming more rapid in the coming decades, with a contribution to total tropospheric bromine of about 3 ppt in 2060. Top-down global annual emissions of the halons were derived using a two-dimensional atmospheric model. The emissions of all four have decreased since peaking in the late 1980s–mid-1990s, but this decline has slowed recently, particularly for H-1301 and H-2402 which have shown no decrease in emissions over the past five years. The UEA (University of East Anglia) top-down model-derived emissions are compared to those reported using a top-down approach by NOAA and AGAGE and the bottom-up estimates of HTOC (Halons Technical Options Committee). The implications of an alternative set of steady-state atmospheric lifetimes are discussed. Using a lifetime of 14 yr or less for H-1211 to calculate top-down emissions estimates would lead to small, or even negative, estimated banks given reported production data. Finally emissions of H-1202, a product of over-bromination during the production process of H-1211, have continued despite reported production of H-1211 ceasing in 2010. This raises questions as to the source of these H-1202 emissions.

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