Black carbon (BC) aerosol strongly absorbs solar radiation, which warms climate. However, accurat... more Black carbon (BC) aerosol strongly absorbs solar radiation, which warms climate. However, accurate estimation of BC's climate effect is limited by the uncertainties of its spatiotemporal distribution, especially over remote oceanic areas. The HIAPER Pole-to-Pole Observation (HIPPO) program from 2009 to 2011 intercepted multiple snapshots of BC profiles over Pacific in various seasons, and revealed a 2 to 5 times overestimate of BC by current global models. In this study, we compared the measurements from aircraft campaigns and satellites, and found a robust association between BC concentrations and satellite-retrieved CO, tropospheric NO2, and aerosol optical depth (AOD) (R(2) > 0.8). This establishes a basis to construct a satellite-based column BC approximation (sBC*) over remote oceans. The inferred sBC* shows that Asian outflows in spring bring much more BC aerosols to the mid-Pacific than those occurring in other seasons. In addition, inter-annual variability of sBC* is ...
Precipitation scavenging (wet deposition) is the dominant loss process for many aerosols but mode... more Precipitation scavenging (wet deposition) is the dominant loss process for many aerosols but model parameterizations of this process are highly uncertain and vary in their extent of coupling to the hydrological cycle, substantially contributing to large uncertainties in the simulated loadings of and radiative forcings from aerosols. The International Global Atmospheric Chemistry Project (IGAC) has recently identified the improvement of wet deposition and scavenging parameterizations in large-scale models as a priority. A reasonable representation of precipitation scavenging is critical for coupled chemistry-aerosol-climate modeling and its application to climate change assessments. In this study we simulate the atmospheric distributions of the aerosol tracers 210Pb and 7Be with the NOAA GFDL AM2 coupled chemistry-climate model (AM2-CHEM). Because of their contrasting (and relatively well-known) sources at low and high altitudes, together with wet deposition as their principal sink, ...
The configuration and performance of a new global atmosphere and land model for climate research ... more The configuration and performance of a new global atmosphere and land model for climate research developed at the Geophysical Fluid Dynamics Laboratory (GFDL) are presented. The atmosphere model, known as AM2, includes a new gridpoint dynamical core, a prognostic cloud scheme, and a multispecies aerosol climatology, as well as components from previous models used at GFDL. The land model, known as LM2, includes soil sensible and latent heat storage, groundwater storage, and stomatal resistance. The performance of the coupled model AM2–LM2 is evaluated with a series of prescribed sea surface temperature (SST) simulations. Particular focus is given to the model's climatology and the characteristics of interannual variability related to E1 Niño– Southern Oscillation (ENSO). One AM2–LM2 integration was performed according to the prescriptions of the second Atmospheric Model Intercomparison Project (AMIP II) and data were submitted to the Program for Climate Model Diagnosis and Interc...
... AM Fiore,1 FJ Dentener,2 O. Wild,3 C. Cuvelier,2 MG Schultz,4 P. Hess,5 C. Textor,6,7 M. Schu... more ... AM Fiore,1 FJ Dentener,2 O. Wild,3 C. Cuvelier,2 MG Schultz,4 P. Hess,5 C. Textor,6,7 M. Schulz,7 RM Doherty,8 LW Horowitz,1 IA MacKenzie,8 MG Sanderson,9 DT Shindell,10 DS Stevenson,8 S. Szopa,7 R. Van Dingenen,2 G. Zeng,11,12 C. Atherton,13,14 D. Bergmann,13 ...
Black carbon (BC) aerosol strongly absorbs solar radiation, which warms climate. However, accurat... more Black carbon (BC) aerosol strongly absorbs solar radiation, which warms climate. However, accurate estimation of BC's climate effect is limited by the uncertainties of its spatiotemporal distribution, especially over remote oceanic areas. The HIAPER Pole-to-Pole Observation (HIPPO) program from 2009 to 2011 intercepted multiple snapshots of BC profiles over Pacific in various seasons, and revealed a 2 to 5 times overestimate of BC by current global models. In this study, we compared the measurements from aircraft campaigns and satellites, and found a robust association between BC concentrations and satellite-retrieved CO, tropospheric NO2, and aerosol optical depth (AOD) (R(2) > 0.8). This establishes a basis to construct a satellite-based column BC approximation (sBC*) over remote oceans. The inferred sBC* shows that Asian outflows in spring bring much more BC aerosols to the mid-Pacific than those occurring in other seasons. In addition, inter-annual variability of sBC* is ...
Precipitation scavenging (wet deposition) is the dominant loss process for many aerosols but mode... more Precipitation scavenging (wet deposition) is the dominant loss process for many aerosols but model parameterizations of this process are highly uncertain and vary in their extent of coupling to the hydrological cycle, substantially contributing to large uncertainties in the simulated loadings of and radiative forcings from aerosols. The International Global Atmospheric Chemistry Project (IGAC) has recently identified the improvement of wet deposition and scavenging parameterizations in large-scale models as a priority. A reasonable representation of precipitation scavenging is critical for coupled chemistry-aerosol-climate modeling and its application to climate change assessments. In this study we simulate the atmospheric distributions of the aerosol tracers 210Pb and 7Be with the NOAA GFDL AM2 coupled chemistry-climate model (AM2-CHEM). Because of their contrasting (and relatively well-known) sources at low and high altitudes, together with wet deposition as their principal sink, ...
The configuration and performance of a new global atmosphere and land model for climate research ... more The configuration and performance of a new global atmosphere and land model for climate research developed at the Geophysical Fluid Dynamics Laboratory (GFDL) are presented. The atmosphere model, known as AM2, includes a new gridpoint dynamical core, a prognostic cloud scheme, and a multispecies aerosol climatology, as well as components from previous models used at GFDL. The land model, known as LM2, includes soil sensible and latent heat storage, groundwater storage, and stomatal resistance. The performance of the coupled model AM2–LM2 is evaluated with a series of prescribed sea surface temperature (SST) simulations. Particular focus is given to the model's climatology and the characteristics of interannual variability related to E1 Niño– Southern Oscillation (ENSO). One AM2–LM2 integration was performed according to the prescriptions of the second Atmospheric Model Intercomparison Project (AMIP II) and data were submitted to the Program for Climate Model Diagnosis and Interc...
... AM Fiore,1 FJ Dentener,2 O. Wild,3 C. Cuvelier,2 MG Schultz,4 P. Hess,5 C. Textor,6,7 M. Schu... more ... AM Fiore,1 FJ Dentener,2 O. Wild,3 C. Cuvelier,2 MG Schultz,4 P. Hess,5 C. Textor,6,7 M. Schulz,7 RM Doherty,8 LW Horowitz,1 IA MacKenzie,8 MG Sanderson,9 DT Shindell,10 DS Stevenson,8 S. Szopa,7 R. Van Dingenen,2 G. Zeng,11,12 C. Atherton,13,14 D. Bergmann,13 ...
Uploads
Papers by Larry Horowitz