scholarly journals Tracking Africa’s Inferno

2000 ◽  
Vol 122 (12) ◽  
pp. 66-70
Author(s):  
Michael Valenti
Keyword(s):  
Carbon Monoxide ◽  
Field Experiment ◽  
South African ◽  
Correlation Spectroscopy ◽  
The Other ◽  
Absorption Bands ◽  
Infrared Radiance ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Aircraft Study

This article focuses on instruments aboard an orbiting satellite and high-flying aircraft study grass fires that straddle a continent. NASA designed its $1.3 billion Terra to be the flagship in a new series of Earth-observing satellites that will study phenomena affecting the climate. The instruments carried by Terra that were most active during the Safari 2000 field experiment were Moderate-Resolution Imaging Spectro-Radiometer (MODIS), Multi-Angle Imaging Spectro-Radiometer (MISR), and Measurements of Pollution in the Troposphere (MOPITT). MOPITT accomplishes its mission by using gas correlation spectroscopy to measure rising and reflected infrared radiance in three absorption bands of carbon monoxide and methane. The Terra’s Safari 2000 observations were augmented by measurements taken by instruments aboard several aircraft, including the high-altitude Lockheed-Martin ER-2 that NASA flew from Pietersburg, South Africa, as part of the African field experiment. The South African Weather Bureau contributed two Aerocommander 690A aircraft to Safari 2000. One of the twin-engine, turboprop planes was used for aerosol research, while the other one helped validate the carbon monoxide measurements obtained by MOPITT.

scholarly journals Stability Assessment of OCO-2 Radiometric Calibration Using Aqua MODIS as a Reference

2020 ◽  
Vol 12 (8) ◽  
pp. 1269 ◽  
Author(s):  
Shanshan Yu ◽  
Robert Rosenberg ◽  
Carol Bruegge ◽  
Lars Chapsky ◽  
Dejian Fu ◽  
...  
Keyword(s):  
Small Error ◽  
The Other ◽  
High Spectral Resolution ◽  
Radiometric Calibration ◽  
Stability Assessment ◽  
Calibration And Validation ◽  
Solar Observations ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

With three imaging grating spectrometers, the Orbiting Carbon Observatory-2 (OCO-2) measures high spectral resolution spectra ( λ / Δ λ ≈ 19,000) of reflected solar radiation within the molecular oxygen (O 2 ) A-band at 0.765 μ m and two carbon dioxide (CO 2 ) bands at 1.61 and 2.06 μ m. OCO-2 uses onboard lamps with a reflective diffuser, solar observations through a transmissive diffuser, lunar measurements, and surface targets for radiometric calibration and validation. Separating calibrator aging from instrument degradation poses a challenge to OCO-2. Here we present a methodology for trending the OCO-2 Build 8R radiometric calibration using OCO-2 nadir observations over eight desert sites and nearly simultaneous observations from Moderate Resolution Imaging Spectroradiometer (MODIS) with sensor viewing zenith angles of 15 ± 0.5 ∘ . For the O 2 A-band, this methodology is able to quantify a drift of −0.8 ± 0.1% per year and capture a small error in correcting the aging of the solar calibrator. For the other two OCO-2 bands, no measurable changes were seen, indicating less than 0.1% and less than 0.3% per year drift in the radiometric calibration of Band 2 and Band 3, respectively.

Pre-eruptive diffuse heating of volcanoes

2020 ◽  
Author(s):  
Társilo Girona ◽  
Vincent Realmuto ◽  
Paul Lundgren
Keyword(s):  
Volcanic Eruptions ◽  
Hydrothermal Activity ◽  
Surface Warming ◽  
New Horizons ◽  
Infrared Radiance ◽  
Magma Reservoirs ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Surface Manifestation ◽  
Radiance Data

<p>Identifying the observables that warn of volcanic unrest and impending eruptions is one of the greatest challenges in the management of natural disasters. An important but scarcely explored observable is diffuse heating, that is, the heat released passively through the ground. Diffuse heating represents one of the major energy sources in active volcanoes during inter-eruptive periods, and can dominate over the elastic energy released during seismic and deformation events. However, many questions remain open: Is there a direct correlation between diffuse heating and the subsurface processes that precede volcanic eruptions? To what extent are volcanic eruptions preceded by an enhancement of the diffuse emissions of heat? We address these questions by analyzing 16.5 years of long-wavelength (10.780 – 11.280 μm) thermal infrared radiance data recorded over nine volcanoes by the moderate-resolution imaging spectroradiometers (MODIS instruments) aboard NASA's Terra and Aqua satellites; this amounts to >35 TB of data and >210,000 MODIS scenes. Our statistical analysis reveals that volcanic edifices get warm for several years before magmatic, phreatic and hydrothermal eruptions. This pre-eruptive warming has been observed at Ontake (Japan), Ruapehu (New Zealand), Domuyo (Argentina), Calbuco (Chile), Redoubt and Okmok (Alaska), Pico do Fogo (Cape Verde), El Hierro (Spain), and Agung (Indonesia) volcanoes. In particular, we found pre-eruptive increases of up to ~1.5 K in the median temperature of the volcanic edifices; this, based on an energy balance, reflects increases of heat flux of up to 10 W/m<sup>2</sup>. We theorize that the pre-eruptive surface warming of volcanoes is the surface manifestation of shallow hydrothermal activity. Our retrospective analysis is especially relevant, since several of the eruptions analyzed did occur with little or no warning (e.g., the 2014 phreatic eruption of Ontake and the 2015 magmatic eruption of Calbuco). The possibility of tracking temporal changes of diffuse heating using satellite data opens new horizons to study the thermal reactivation of magma reservoirs and improve the forecasting of volcanic eruptions.</p>

scholarly journals Spatiotemporal Investigations of Multi-Sensor Air Pollution Data over Bangladesh during COVID-19 Lockdown

2021 ◽  
Vol 13 (5) ◽  
pp. 877
Author(s):  
Zhongfeng Qiu ◽  
Md. Arfan Ali ◽  
Janet E. Nichol ◽  
Muhammad Bilal ◽  
Pravash Tiwari ◽  
...  
Keyword(s):  
Air Pollution ◽  
The Other ◽  
Slight Reduction ◽  
Average Increase ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Pm2.5 And Pm10 ◽  
Monitoring Service ◽  
Aerosol Types

This study investigates spatiotemporal changes in air pollution (particulate as well as gases) during the COVID-19 lockdown period over major cities of Bangladesh. The study investigated the aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra and Aqua satellites, PM2.5 and PM10 from Copernicus Atmosphere Monitoring Service (CAMS), and NO2 and O3 from TROPOMI-5P, from March to June 2019–2020. Additionally, aerosol subtypes from the Cloud-Aerosol Lidar and Infrared Pathfinder (CALIPSO) were used to explore the aerosol types. The strict lockdown (26 March–30 May 2020) led to a significant reduction in AOD (up to 47%) in all major cities, while the partial lockdown (June 2020) led to increased and decreased AOD over the study area. Significant reductions in PM2.5 (37–77%) and PM10 (33–70%) were also observed throughout the country during the strict lockdown and partial lockdown. The NO2 levels decreased by 3–25% in March 2020 in the cities of Rajshahi, Chattogram, Sylhet, Khulna, Barisal, and Mymensingh, in April by 3–43% in Dhaka, Chattogram, Khulna, Barisal, Bhola, and Mymensingh, and May by 12–42% in Rajshahi, Sylhet, Mymensingh, and Rangpur. During the partial lockdown in June, NO2 decreased (9–35%) in Dhaka, Chattogram, Sylhet, Khulna, Barisal, and Rangpur compared to 2019. On the other hand, increases were observed in ozone (O3) levels, with an average increase of 3–12% throughout the country during the strict lockdown and only a slight reduction of 1–3% in O3 during the partial lockdown. In terms of aerosol types, CALIPSO observed high levels of polluted dust followed by dust, smoke, polluted continental, and clean marine-type aerosols over the country in 2019, but all types were decreased during the lockdown. The study concludes that the strict lockdown measures were able to significantly improve air quality conditions over Bangladesh due to the shutdown of industries, vehicles, and movement of people.

scholarly journals Tropospheric carbon monoxide variability from AIRS and IASI under clear and cloudy conditions

2013 ◽  
Vol 13 (6) ◽  
pp. 16337-16366 ◽  
Author(s):  
J. Warner ◽  
F. Carminati ◽  
Z. Wei ◽  
W. Lahoz ◽  
J.-L. Attié
Keyword(s):  
Carbon Monoxide ◽  
Emission Inventory ◽  
Correlation Coefficients ◽  
Retrieval Algorithm ◽  
Atmospheric Infrared Sounder ◽  
Fire Emissions ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Cloud Mask

Abstract. We study the Carbon Monoxide (CO) variability in the last decade measured by NASA's Atmospheric InfraRed Sounder (AIRS) on the Earth Observing Systems (EOS)/Aqua satellite and Europe's Infrared Atmospheric Sounder Interferometer (IASI) on MetOp platform. The focus of this study is to analyze CO variability and short-term trends separately for background CO and new emissions based on a new statistical approach. The AIRS Level 2 (L2) retrieval algorithm, as well as the IASI products from NOAA, utilizes cloud clearing to treat cloud contaminations in the signals; and this increases the data coverage significantly to a yield of more than 50% of the total measurements (Susskind et al., 2003). We first study if the cloud clearing affects CO retrievals and the subsequent trend studies by using the collocated Moderate Resolution Imaging Spectroradiometer (MODIS) (Ackerman et al., 1998) cloud mask to identify AIRS clear sky scenes. We then separate AIRS CO data into clear and cloud-cleared scenes and into background and new emissions, respectively. Furthermore, we carry out a similar study for the IASI CO and discuss the consistency with AIRS. We validate the CO variability of the emissions developed from AIRS against other emission inventory databases (i.e., Global Fire Emissions Database – GFED3 and the MACC/CityZEN UE – MACCity) and calculate that the correlation coefficients between the AIRS CO emissions and the emission inventory databases are 0.726 for the Northern Hemisphere (NH) and 0.915 for the Southern Hemisphere (SH).

scholarly journals AN INTER-COMPARISON OF THE SPATIAL AND TEMPORAL CHARACTERISTICS OF CO OVER HIGH FIRE REGIONS BASED ON MOPITT AND GFED

2019 ◽  
Vol XLII-3/W9 ◽  
pp. 119-123
Author(s):  
C. Y. Lin ◽  
S. Wang ◽  
J. B. Cohen
Keyword(s):  
Carbon Monoxide ◽  
Measurement Error ◽  
Long Range Transport ◽  
Spatial And Temporal Distributions ◽  
Short Period ◽  
Range Transport ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Spatial And Temporal Characteristics

Abstract. The spatial and temporal distributions of Carbon Monoxide (CO) as measured by the Moderate Resolution Imaging spectroradiometer (MOPITT) instrument are analyzed in depth in this work. We specifically look at how these values, their statistics and their trends behave from 2000 to 2018 over regions defined as high fire regions, based on the carbon emissions product from the Global Fire Emission Database (GFED). Our results indicate that there are significant differences in the timing, duration, and magnitude of the fires as measured by MOPITT over different high fire regions. Our results are also different from past studies which have relied upon remotely sensed aerosol measurements, such as AOD. Over these high fire regions, we find that the fires contribute the vast majority of the CO loading, which always occurs over a short period of time, on order of weeks. Over 7 regions studied, we have found a statistically significant decreasing trend, albeit smaller than the measurement error. The correlation between the MOPITT and GFED approaches if found to be reliable over the regions where the two datasets overlap. We finally find evidence for possible long-range transport of CO from one fire region to another.

The Final ‘Thank You’

Derrida Today ◽  
2010 ◽  
Vol 3 (1) ◽  
pp. 21-36
Author(s):  
Grant Farred
Keyword(s):  
South Africa ◽  
South African ◽  
Jacques Derrida ◽  
Political Transition ◽  
The Other ◽  
World Cup ◽  
The Core ◽  
Nelson Mandela ◽  
Black President ◽  
The Moment

‘The Final “Thank You”’ uses the work of Jacques Derrida and Friedrich Nietzsche to think the occasion of the 1995 rugby World Cup, hosted by the newly democratic South Africa. This paper deploys Nietzsche's Zarathustra to critique how a figure such as Nelson Mandela is understood as a ‘Superman’ or an ‘Overhuman’ in the moment of political transition. The philosophical focus of the paper, however, turns on the ‘thank yous’ exchanged by the white South African rugby captain, François Pienaar, and the black president at the event of the Springbok victory. It is the value, and the proximity and negation, of the ‘thank yous’ – the relation of one to the other – that constitutes the core of the article. 1

Remote Sensing Based Assessment of Agricultural Droughts in Sub-Watersheds of Upper Bhima Basin, India

2019 ◽  
Vol 2 (2) ◽  
pp. 105-111 ◽  
Author(s):  
Nayan Zagade ◽  
Ajaykumar Kadam ◽  
Bhavana Umrikar ◽  
Bhagyashri Maggirwar
Keyword(s):  
Remote Sensing ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Agricultural Sector ◽  
Health Index ◽  
Drought Assessment ◽  
Drought Conditions ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Vegetation Health Index

Drought assessment for agricultural sector is vital in order to deal with the water scarcity in Ahmednagar and Pune districts, particularly in sub-watersheds of upper catchment of the River Bhima. Moderate Resolution Imaging Spectro-radiometer (MODIS) satellite data (2000, 2002, 2009, 2014, 2015 and 2017) for the years receiving less rainfall have been procured and various indices were computed to understand the intensity of agricultural droughts in the area. Vegetation health index (VHI) is computed on the basis of vegetation moisture, vegetation condition and land surface temperature condition. Most of the reviewed area shows moderate to extreme drought conditions.

Impact of aerosol on air temperature in Baghdad

2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Yaseen Kadhim Abbas Al-Timimi ◽  
Ali Challob Khraibet
Keyword(s):  
Temperature Variation ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Air Temperature ◽  
Strong Correlation ◽  
Imaging Spectrometer ◽  
Moderate Resolution ◽  
Resolution Imaging

Aerosol Optical Depth (AOD) is the measure of aerosol distributed with a Column of air from earth’s surface to the top of atmosphere, in this study, temperature variation of aerosol optical depth (AOD) in Baghdad was analyzed Moderate Resolution Imaging Spectrometer (MODIS) from Terra and its relationship with temperature for the period 2003 – 2015 were examined. The highest values for mean seasonal AOD were observed in spring and summer and the maximum AOD values ranged from 0.50 to 0.58 by contrast minimum AOD values ranging from 0.30 to 0.41 were found in winter and autumn. Results of study also showed that the temperature (max., min., mean air temperature and DTR) have a strong correlation with AOD (0.82, 0.83, 0.82 and 0.65) respectively.

scholarly journals Influence of Straw Burning on Urban Air Pollutant Concentrations in Northeast China

2019 ◽  
Vol 16 (8) ◽  
pp. 1379 ◽  
Author(s):  
Zhenzhen Wang ◽  
Jianjun Zhao ◽  
Jiawen Xu ◽  
Mingrui Jia ◽  
Han Li ◽  
...  
Keyword(s):  
Northeast China ◽  
Arable Land ◽  
Pollution Index ◽  
Air Pollutant ◽  
Thermal Anomalies ◽  
Pollutant Concentrations ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Straw Burning ◽  
Moderate Resolution Imaging Spectroradiometer

Northeast China is China’s primary grain production base. A large amount of crop straw is incinerated every spring and autumn, which greatly impacts air quality. To study the degree of influence of straw burning on urban pollutant concentrations, this study used The Moderate-Resolution Imaging Spectroradiometer/Terra Thermal Anomalies & Fire Daily L3 Global 1 km V006 (MOD14A1) and The Moderate-Resolution Imaging Spectroradiometer/Aqua Thermal Anomalies and Fire Daily L3 Global 1 km V006 (MYD14A1) data from 2015 to 2017 to extract fire spot data on arable land burning and to study the spatial distribution characteristics of straw burning on urban pollutant concentrations, temporal variation characteristics and impact thresholds. The results show that straw burning in Northeast China is concentrated in spring and autumn; the seasonal spatial distributions of PM2.5, PM10 andAir Quality Index (AQI) in 41 cities or regions in Northeast China correspond to the seasonal variation of fire spots; and pollutants appear in the peak periods of fire spots. In areas where the concentration coefficient of rice or corn is greater than 1, the number of fire spots has a strong correlation with the urban pollution index. The correlation coefficient R between the number of burned fire spots and the pollutant concentration has a certain relationship with the urban distribution. Cities are aggregated in geospatial space with different R values.

scholarly journals A Climatological Assessment of Intense Desert Dust Episodes over the Broader Mediterranean Basin Based on Satellite Data

2021 ◽  
Vol 13 (15) ◽  
pp. 2895
Author(s):  
Maria Gavrouzou ◽  
Nikolaos Hatzianastassiou ◽  
Antonis Gkikas ◽  
Christos J. Lolis ◽  
Nikolaos Mihalopoulos
Keyword(s):  
Mediterranean Basin ◽  
Eastern Mediterranean ◽  
Mean Value ◽  
Early Spring ◽  
Dust Aerosol ◽  
Ozone Monitoring Instrument ◽  
Central Mediterranean ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

A satellite algorithm able to identify Dust Aerosols (DA) is applied for a climatological investigation of Dust Aerosol Episodes (DAEs) over the greater Mediterranean Basin (MB), one of the most climatologically sensitive regions of the globe. The algorithm first distinguishes DA among other aerosol types (such as Sea Salt and Biomass Burning) by applying threshold values on key aerosol optical properties describing their loading, size and absorptivity, namely Aerosol Optical Depth (AOD), Aerosol Index (AI) and Ångström Exponent (α). The algorithm operates on a daily and 1° × 1° geographical cell basis over the 15-year period 2005–2019. Daily gridded spectral AOD data are taken from Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua Collection 6.1, and are used to calculate the α data, which are then introduced into the algorithm, while AI data are obtained by the Ozone Monitoring Instrument (OMI) -Aura- Near-UV aerosol product OMAERUV dataset. The algorithm determines the occurrence of Dust Aerosol Episode Days (DAEDs), whenever high loads of DA (higher than their climatological mean value plus two/four standard deviations for strong/extreme DAEDs) exist over extended areas (more than 30 pixels or 300,000 km2). The identified DAEDs are finally grouped into Dust Aerosol Episode Cases (DAECs), consisting of at least one DAED. According to the algorithm results, 166 (116 strong and 50 extreme) DAEDs occurred over the MB during the study period. DAEDs are observed mostly in spring (47%) and summer (38%), with strong DAEDs occurring primarily in spring and summer and extreme ones in spring. Decreasing, but not statistically significant, trends of the frequency, spatial extent and intensity of DAECs are revealed. Moreover, a total number of 98 DAECs was found, primarily in spring (46 DAECs) and secondarily in summer (36 DAECs). The seasonal distribution of the frequency of DAECs varies geographically, being highest in early spring over the eastern Mediterranean, in late spring over the central Mediterranean and in summer over the western MB.

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