Fagbeja Mofoluso A., PhD, winner of the 2012 Ian McCrae Award, reports on the two conferences he attended, supported by the grant. Based on the findings from his doctoral study, Applying Remote Sensing, GIS and Emission Estimation Techniques to Air Quality and Carbon Dioxide Emissions Measurements and Monitoring in the Niger Delta, he submitted two papers for presentation at the ASPRS and the AAG conferences, both of which were accepted for oral presentation.
American Society of Photogrammetry and Remote Sensing (ASPRS) 2013 Annual Conference in Baltimore, MD USA, 24-28 March
The theme of the
Conference was Confluence by the Bay – A Gathering of Geospatial Insights. The Conference drew participation from thousands of geospatial professionals and practitioners from all over the world to discuss progress and recent developments in various fields of geospatial techniques as contained in over 400 technical presentations.
I presented a paper titled,
A Subjective Assessment of the Suitability of SCIAMACHY Total Column CO Measurements to Interpolate Reliable Concentration Estimates Over a Low-latitude Region. The paper focused on the relevance, challenges and opportunities of satellite-based measurement to provide reliable data to support the estimation of carbon monoxide (CO) concentrations considering the climatic conditions in the Niger Delta region of Nigeria over the period from January 2003 to December 2005. The relevance of the paper is to identify the support satellite-based measurements could provide for air quality assessment in economically-constrained developing countries within the low latitudes that cannot afford networks of ground-based monitoring stations.
A subjective reliability assessment was carried out based on the number and spatial distribution of the SCIAMACHY sensor column measurements available on a monthly basis. The implementation process sub-divided the Niger Delta region into four sections – 2 inland or northern and two southern or coastal sections. The results showed varying degree of reliability both spatially and temporally (or seasonally). Over the 36-month period of study, only nine months had reliable estimates generated over the entire region. Additional six months produced reliable estimates over three out of four sections of the Niger Delta. Reliable estimates were generated over two sections (the northern sections) of the region in 4 months, while a period of seven months produced reliable estimates in only one section of the region. There were no satellite measurements for June 2003 and December 2005. A total of seven months recorded unreliable estimates over the entire region.
Observations from the results showed that more reliable estimates were generated over the inland areas (68%) than the coastal areas (35%). Seasonally, more reliable estimates were generated during the dry season (61%) than during the wet season (46%). The extent of reliability generated both spatially and seasonally depends on the influence of climatic conditions and anthropogenic activities – rainfall and relative humidity during the wet season, and dust from the Sahara Desert and biomass burning during the dry season. High intensities of these factors also reduce the efficiency of retrieval algorithms to extract good quality CO measurement data.
Whilst acknowledging the key roles satellite sensor measurements stand to play in supporting air quality assessment as demonstrated by the CO reliability assessment, the paper concluded by suggesting the need for additional research to consider combining measurements from other satellite sensors to increase the number of available column measurements and establishment of ground-based air quality monitoring stations to support satellite observations within the low latitudes.
The paper is published in the Proceedings of the ASPRS 2013 Annual Conference. An invitation has also been extended to consider submission of the paper for publication in the peer-reviewed Photogrammetric Engineering and Remote Sensing (PE&RS) journal.
Association of American Geographers (AAG) 2013 Annual General Meeting in Los Angeles, CA USA, 9-13 April 2013
The 2013 Annual Meeting of the Association of American Geographers (AAG) held in Los Angeles, California USA, had thousands of researchers and Geographers from all over the world. At the Conference, I presented a paper titled,
The need for improved sensing technology for estimating concentrations of air pollutants at ground levels in low latitude climates. In addition to presenting a paper, I was the Chair of the Remote Sensing session that took place at the Biltmore Hotel on Friday, 12 April, 2013. The session had 5 paper presentations on different application areas of satellite remote sensing.
The presentation highlighted the current roles of satellite-based observations in climate change, ozone layer depletion, air quality assessment and weather studies. In addition, the presentation identified the international applications of satellite technology in air pollution management, which include the assessment of compliance of nations to international treaties such as the UNFCCC, and monitoring air pollution through the provision of information on sources, sinks and transport of air pollution. Given economic, security and accessibility considerations, space-based measurements of concentrations of air pollutants may be invaluable in developing countries for urban air pollution assessment, collection of data in remote and inaccessible areas, and reduction in costs of air pollution monitoring in areas where the establishment of ground-based monitoring stations are considered too expensive or not given due priority.
In order to critically assess the extent to which satellite sensor measurements could provide support for air quality monitoring within the low latitudes, the results of the study carried out to assess the suitability of specific satellite sensors to provide reliable concentration estimates over the Niger Delta region of Nigeria was presented. The satellite sensors, data products and the measured trace gases used for the study were:
- Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) WFM-DOAS monthly total column CO;
- Global Ozone Monitoring Experiment (GOME) monthly tropospheric column NO2 at 0.25o x 0.25o grid resolution; and
- Ozone Monitoring Experiment (OMI) monthly tropospheric column O3 at 1.25o longitude x 1o latitude grid resolution.
The identified limitations to satellite-based assessment of air quality within the low latitudes include
- Inability of currently existing satellite sensors to directly measure ground-level concentrations of air pollutants where it has implications for air quality;
- Climatic conditions which hinder data retrieval and reduce number of available column measurements;
- Inadequate ground-based monitoring stations within the low latitudes to calibrate satellite sensor measurements;
- Inadequate infrastructure and technical capabilities to infer ground level concentrations from satellite sensor column measurements; and
- Inadequate measurements to carry out daily assessment of pollutant concentrations.
In order to enhance the application and integration of satellite-based measurements in air quality assessment for developing countries within the low latitudes, the presentation made the following recommendations:
- Additional research and development in:
- Air pollution monitoring satellite sensors dedicated for the low-latitude belt
- Constellation of micro-satellites that carry high-resolution air pollutant monitoring instruments in order to increase revisit time, imaging opportunities, data quantity and reduce costs
- Retrieval algorithms that adequately correct for extensive cloud cover, high atmospheric water vapour content and haze
- Understanding the relationships between concentration of trace gases and measurable climatic conditions
- Inferring ground-level concentrations of air pollutants from satellite-based measurements
- International collaboration to build capacity in the application of satellite technology to air quality measurement and monitoring.
- Concerted support for developing countries within low latitudes to establish the minimum required air quality ground monitoring stations to enhance validation of satellite measurements, thereby improve data quality.
- Incorporation of satellite-based measurements into air quality management frameworks for developing countries.