Aerosol direct radiative effects over the northwest atlantic, northwest pacific, and north indian oceans: estimates based on in-situ chemical and optical measurements and chemical transport modeling
Bates, T. S.
Anderson, T. L.
O'Dowd, C. D.
Quinn, P. K.
Ravishankara, A. R.
Savoie, D. L.
Schwartz, S. E.
Weber, R. J.
MetadataShow full item record
This item's downloads: 0 (view details)
Cited 106 times in Scopus (view citations)
Bates, T. S. Anderson, T. L.; Baynard, T.; Bond, T.; Boucher, O.; Carmichael, G.; Clarke, A.; Erlick, C.; Guo, H.; Horowitz, L.; Howell, S.; Kulkarni, S.; Maring, H.; McComiskey, A.; Middlebrook, A.; Noone, K.; O'Dowd, C. D.; Ogren, J.; Penner, J.; Quinn, P. K.; Ravishankara, A. R.; Savoie, D. L.; Schwartz, S. E.; Shinozuka, Y.; Tang, Y.; Weber, R. J.; Wu, Y. (2006). Aerosol direct radiative effects over the northwest atlantic, northwest pacific, and north indian oceans: estimates based on in-situ chemical and optical measurements and chemical transport modeling. Atmospheric Chemistry and Physics 6 , 1657-1732
The largest uncertainty in the radiative forcing of climate change over the industrial era is that due to aerosols, a substantial fraction of which is the uncertainty associated with scattering and absorption of shortwave ( solar) radiation by anthropogenic aerosols in cloud-free conditions (IPCC, 2001). Quantifying and reducing the uncertainty in aerosol influences on climate is critical to understanding climate change over the industrial period and to improving predictions of future climate change for assumed emission scenarios. Measurements of aerosol properties during major field campaigns in several regions of the globe during the past decade are contributing to an enhanced understanding of atmospheric aerosols and their effects on light scattering and climate. The present study, which focuses on three regions downwind of major urban/population centers ( North Indian Ocean (NIO) during INDOEX, the Northwest Pacific Ocean (NWP) during ACE-Asia, and the Northwest Atlantic Ocean (NWA) during ICARTT), incorporates understanding gained from field observations of aerosol distributions and properties into calculations of perturbations in radiative fluxes due to these aerosols. This study evaluates the current state of observations and of two chemical transport models ( STEM and MOZART). Measurements of burdens, extinction optical depth (AOD), and direct radiative effect of aerosols (DRE - change in radiative flux due to total aerosols) are used as measurement-model check points to assess uncertainties. In-situ measured and remotely sensed aerosol properties for each region ( mixing state, mass scattering efficiency, single scattering albedo, and angular scattering properties and their dependences on relative humidity) are used as input parameters to two radiative transfer models (GFDL and University of Michigan) to constrain estimates of aerosol radiative effects, with uncertainties in each step propagated through the analysis. Constraining the radiative transfer calculations by observational inputs increases the clear-sky, 24-h averaged AOD ( 34 +/- 8%), top of atmosphere (TOA) DRE ( 32 +/- 12%), and TOA direct climate forcing of aerosols (DCF - change in radiative flux due to anthropogenic aerosols) ( 37 +/- 7%) relative to values obtained with "a priori" parameterizations of aerosol loadings and properties (GFDL RTM). The resulting constrained clear-sky TOA DCF is - 3.3 +/- 0.47, - 14 +/- 2.6, - 6.4 +/- 2.1W m(-2) for the NIO, NWP, and NWA, respectively. With the use of constrained quantities ( extensive and intensive parameters) the calculated uncertainty in DCF was 25% less than the "structural uncertainties" used in the IPCC-2001 global estimates of direct aerosol climate forcing. Such comparisons with observations and resultant reductions in uncertainties are essential for improving and developing confidence in climate model calculations incorporating aerosol forcing.
Showing items related by title, author, creator and subject.
Measurement and analysis of aerosol and black carbon in the southwestern united states and panama and their dependence on air mass origin Junker, C.; Sheahan, J. N.; Jennings, S. G.; O'Brien, P.; Hinds, B. D.; Martinez-Twary, E.; Hansen, A. D. A.; White, C.; Garvey, D. M.; Pinnick, R. G. (Wiley-Blackwell, 2004-07-07)Total aerosol mass loading, aerosol absorption, and black carbon ( BC) content were determined from aerosol collected on 598 quartz fiber filters at a remote, semiarid site near Orogrande, New Mexico from December 1989 to ...
Advances in characterization of size-resolved organic matter in marine aerosol over the north atlantic Cavalli, F. (Wiley-Blackwell, 2004-01-01)Size-segregated marine aerosols were collected at Mace Head Atmospheric Research Station (Ireland) during spring and autumn 2002 corresponding with the phytoplankton bloom periods in the North Atlantic. Strict control of ...
Fossum, Kirsten (NUI Galway, 2018-12-06)This work investigates marine aerosol physico-chemical properties (e.g. size and chemistry) and its Cloud Condensation Nuclei (CCN) properties under natural background conditions. Black carbon (BC), a tracer for anthropogenic ...