Observation And Validation Of Methane From Ft-ir Over Addis Ababa

The concentration of methane, the most abundant organic trace gas in the atmospherernhas increased dramatically, over the past few centuries, to more than double its value. Thernincrease in its concentration is of special concern because of its e ects on climate and atmosphericrnchemistry. High resolution Mid infra-red (MIR) solar absorption FTIR spectrarnhave been routinely recorded between May 2009 and Nov 2010 at Addis Ababa Observatoryrn(9.01oN, 38.76oE). By analyzing the shape of the pressure dependent absorption linesrnand their di erent temperature sensitivities, the vertical distribution and column amountrnof methane is retrieved. Unique time series of the column abundances and volume mixingrnratio (vmr) of methane are presented. The e ects of both dynamical and chemical seasonallyrnvarying trace gas cycles can be seen in the retrieved pro les. These include littlernvariabilities in summer and winter seasons, which is typical of tropical atmosphere. Particularrnevents are selected and origin of air mass rnow is identi ed with the help of AirrnResource Laboratory's (ARL) Hybrid Single Particle Lagrangian Integrated Trajectoryrn(HYSPLIT) model. A detailed error analysis has been performed for each pro le. Thernoutput from Atmospheric Infra-Red Sounder (AIRS) is compared to the total columnrnamount. Results agree well with a correlation coe cient of 0.8

Get Full Work

Report copyright infringement or plagiarism