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A Lagrangian Study of Southeast Pacific Boundary Layer Clouds
(2013-04-17)
Low clouds lie at the heart of climate feedback uncertainties. The representation of clouds in global climate models relies on parameterization of many sub-grid scale processes that are crucial to understanding cloud responses to climate; low clouds in particular exist as a result of tightly coupled microphysical, mesoscale, ...
Aerosol cloud interactions in southeast Pacific stratocumulus: satellite observations, in situ data and regional modeling
(2013-07-23)
The influence of anthropogenic aerosols on cloud radiative properties in the persistent southeast Pacific stratocumulus deck is investigated using MODIS satellite observations, in situ data from the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx), and WRF-Chem, a regional model with interactive chemistry ...
Biogeochemical cycling of mercury in the atmosphere-ocean-land system: Global and regional modeling
(2013-07-23)
Mercury (Hg) is a ubiquitous trace metal in the environment originating from both natural and anthropogenic sources. It is a pollutant of concern because of the adverse human health effects caused by the consumption of fish and seafood containing methylmercury, which is a neurotoxin. Through development of two transport and ...
Detection and Attribution of Global Surface Air Temperature Change in the Instrumental Record
(2013-07-23)
This study investigates the spatial and temporal variability of surface air temperature (SAT) in the instrumental record of climate, emphasizing the detection of SAT change in the presence of natural variability as well as the attribution of SAT variability and trends to atmospheric circulation changes, as reflected in ...
Understanding changes in the stratospheric circulation from observations and simulations
(2013-07-23)
This study investigates the variation of the Brewer-Dobson circulation (BDC) in the stratosphere on interannual and decadal timescales from both observations and numerical simulations. Lower stratospheric temperature has been employed to indicate changes of the BDC over the past few decades. Based on regression analysis and ...
Assimilation of Time-averaged Pseudoproxies for Climate Reconstruction
(2013-07-23)
We examine the efficacy of a novel ensemble data assimilation (DA) technique in climate field reconstructions (CFR) of surface temperature. We perform four pseudoproxy experiments with both general circulation model (GCM) and 20th Century Reanalysis (20CR) data by reconstructing surface temperature fields from a sparse network ...
Dynamics of Large-Scale Convective Onset in the Madden-Julian Oscillation
The role of large-scale circulation anomalies in the convective onset of the Madden-Julian Oscillation (MJO) over the Indian Ocean during the Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign, conducted Oct. 2011–Feb. 2012, is explained using radar and rawinsonde observations, reanalysis, and regional model ...
Progressive Mid-latitude Afforestation: Local and Remote Climate Impacts in the Framework of Two Coupled Earth System Models
Vegetation influences the atmosphere in complex and non-linear ways, such that large- scale changes in vegetation cover can drive changes in climate on both local and global scales. Large-scale land surface changes have been shown to introduce excess energy to one hemi- sphere, causing a shift in atmospheric circulation on a ...
On the Influence of Poleward Jet Shift on Shortwave Cloud Feedback in Global Climate Models
Experiments designed to separate the effect of atmospheric warming from the effect of shifts of the eddy-driven jet on shortwave (SW) cloud feedback are performed with three global climate models (GCMs). In each model a warming simulation produces a robust SW cloud feedback dipole, with a negative (positive) feedback in the ...
Microphysics and Southern Ocean Cloud Feedback
Global climate models (GCMs) change their cloud properties in the Southern Ocean (SO) with warming in a qualitatively consistent fashion. Cloud albedo increases in the mid-latitudes and cloud fraction decreases in the subtropics. This creates a distinctive ‘dipole’ structure in the SW cloud feedback. However, the shape of the ...