CO and Aerosols Retrieved from Satellite Thomas Kampe Ball Aerospace Technologies Corp Presented at Remote Sensing Seminar Series University of Colorado April 28 2004 1 CU Remote Sensing Seminar Spring 2004 4 29 2004 Overview Why are CO and Aerosols important from a Climate Standpoint How are this atmospheric constituents being observed from space What are the challenges What does the future hold for remote sensing of aerosols and CO Summary 2 CU Remote Sensing Seminar Spring 2004 4 29 2004 Importance of Aerosols and CO Why is a better understanding of the atmospheric distribution of CO and aerosols important Both CO and aerosols are key components of air pollution and impact air quality Both effect atmospheric chemistry control O3 chemistry and OH Aerosols are key component of global radiative forcing Sulfate aerosols exhibit a negative forcing cooling Mineral dust and black carbon are spectrally absorptive sign of forcing uncertain From IPCC Report 2000 Aerosols are main radiative forcing drivers 3 CU Remote Sensing Seminar Spring 2004 4 29 2004 Radiative Properties of Aerosols Previously accepted scenario Greenhouse gases warm the atmosphere Aerosols primarily sulfates cool the atmosphere by reflecting incident short wave radiation The Problem Aerosols are not white but gray so they absorb some fraction of the incident SW radiation tending to heat the atmosphere This is particularly true for black carbon BC a large component of positive radiative forcing from aerosols is due to BC the question is how much Mineral dust is also spectrally absorptive 4 CU Remote Sensing Seminar Spring 2004 4 29 2004 W hy C ar bon M onox ide C O is one of t he most impor t ant t r ac e gases in t r opospher ic c hem ist r y T h e at m o s ph e r ic o x id at io n r e ac t io n w it h O H is t h e d o minant m e c h anis m o f O H c y c ling in t h e t r opo s ph e r e CO O H CO 2 H O 2 S o u rc e s HO2 N O N O2 OH N O 2 hv N O O O O2 M O3 M N et CO 2 O 2 hv CO 2 O 3 C O is t h e pr i m ar y s ink f or O H M e as ur e m e nt of t im e e volut ion of O 3 and C O ne e d e d t o und e r s t and pr oc e s s e s t h at c ont r ol t r opos ph e r ic O 3 C O has a lif et ime of one t o t hr ee mont hs T r ac e r f o r at m o s ph e r ic t r ac e r s t ud ie s C O S our c es and S inks E st shown in T able B e t t e r und e r s t and ing o f s o ur c e s s ink s T e c h n o lo g ic a l B io m a s s B u r n in g B io g e n ic s O ceans M e th a n e O x id a tio n N M H C O x id a tio n T o ta l S o u r c e s S in k s O H R e a c tio n S o il U p ta k e S tr a to s p h e ric L o s s T o ta l S in k s t r e nd s is a h igh pr io r it y U S G C C R P C ur r e nt k no w le d ge o f C O d is t r ib ut io n lim it e d T r o po s ph e r ic C O inc r e as ing o r d e c r e as ing N ot c le ar 6 C U R e m o te S e n s in g S e m in a r S p rin g 2 0 0 4 Range T g C O y r 1 300 550 300 700 60 160 20 200 400 1000 200 600 1800 2700 Range T g C O y r 1 1400 2600 250 640 100 2100 3000 S o u r c e IP C C 1 9 9 5 4 2 9 2 0 0 4 How are Aerosols and CO being Observed from Space Prior to 1999 satellite measurements of aerosols were limited to one GOES METEOSAT or two AVHRR channels Aerosols were not retrieved over land Due to variability of surface reflectance The Moderate Resolution Imaging Spectroradiometer MODIS first launched on the NASA Terra satellite is providing the first systematic retrievals of aerosols over both ocean and land http modis gsfc nasa gov MODI S Whiskbroom scanning spectroradiometer Spectral coverage 0 412 to 14 3 m 36 bands Retrieves aerosol optical thickness over oceans and portions of continents using VI S NI R bands Maximum sensitivity over dark surf aces i e oceans dark pixel approach over land Separates aerosols into 2 modes fi ne r ef 0 5 m coarse r ef 1 0 m 7 CU Remote Sensing Seminar Spring 2004 4 29 2004 S e p t 2 0 0 0 M O D IS A e r o s o l M O D I S c a n d is t in g u is h b e t w e e n A O D C o a rse m o d e c o a r s e a n d f in e p a r tic le s u s in g m u lt ip le c h a n n e ls fr o m t h e v is ib le to th e n e a r IR C o a rs e a e ro s o l m o d e M a in ly d u s t a n d s e a s a lt R e f le c t s in th e V I S N I R A p p e a r s r e d in t h e V I S d u e t o a b s o r p t io n in th e b lu e S u r f a c e c h a r a c t e r iz a t io n is a n is s u e o v e r la n d F in e a e r o s o l m o …