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Semyon A. Grodsky, Abderrahim Bentamy, James A. Carton, and Rachel T. Pinker

1. Introduction Latent heat flux (LHTFL) links air–sea heat exchange with the hydrological cycle. This evaporative heat loss term balances a significant portion of the surface heat gain due to solar radiation ( da Silva et al. 1994 ). Satellite sensors can measure sea surface temperature (SST), near-surface winds, and humidity and thus provide data for estimating evaporation. Currently, several satellite-based global ocean latent heat flux products are available (e.g., Chou et al. 2003 and

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Yvonne B. L. Hinssen and Maarten H. P. Ambaum

stratospheric warmings are believed to be primarily forced from below by wave activity entering the stratosphere from the troposphere (see also Andrews et al. 1987 ). For example, Charlton and Polvani (2007) show that the 100-hPa heat flux (which is a measure of the upward propagating wave forcing to the stratosphere) is increased in the weeks before the occurrence of a sudden stratospheric warming. Here we examine to which extent the wave forcing of the stratosphere drives the large-scale stratospheric

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Varun S. Murthy and William R. Boos

fluxes in the early stage of TD spinup is less thoroughly explored. Precipitating convection has long been associated with TC intensification ( Palmen 1948 ). It is now widely accepted that storm-scale intensification of the azimuthal wind can be attributed to a radial circulation that converges vorticity, with precipitation falling in the upward branch of that radial circulation ( Emanuel 2003 ; Montgomery and Smith 2017 ). This precipitating ascent occurs in an ensemble of convective updrafts

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Zuohao Cao and Jianmin Ma

1. Introduction Accurate representation of the surface sensible heat flux over the Arctic sea ice is important to characterize the energy transfer between the atmosphere and its underlying surface, and to better understand the interaction occurring in this coupled system ( Cao et al. 2002 ). Precisely modeling the sensible heat flux, however, is a very challenging issue because computation of the surface sensible heat flux in a numerical weather prediction (NWP) model and a general circulation

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Ivan Mammarella, Samuli Launiainen, Tiia Gronholm, Petri Keronen, Jukka Pumpanen, Üllar Rannik, and Timo Vesala

1. Introduction The estimation of energy and scalar turbulent fluxes by eddy covariance (EC) technique is well established and widespread in the micrometeorological community. Long-term measurements of the surface energy balance components and the atmosphere–biosphere exchange of trace gases are essential for assessing the role of vegetation in the climate change perspective. Closed-path eddy covariance (EC) systems are widely used in the flux tower network (Fluxnet) sites around the world to

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Nicholas A. Bond and Meghan F. Cronin

1. Introduction Air–sea interactions are particularly strong in the region of the recirculation gyre south of the Kuroshio Extension in the western North Pacific Ocean. Frequent outbreaks of cold, dry air of continental origin over the relatively warm ocean during winter results in this region experiencing the largest mean surface heat fluxes of the entire Pacific basin ( Josey et al. 1998 ). These heat fluxes are an aspect of the global heat cycle and affect how the net poleward heat transport

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B. A. Forman and S. A. Margulis

1. Introduction An ensemble-based land data assimilation system (LDAS) is an attractive framework to systematically merge modeled and measured estimates of land surface states and fluxes in order to advance scientific understanding (e.g., assessment of hydrologic balance over regional and global scales) while benefiting societal needs (e.g., flood forecasting). However, one significant challenge in constructing an LDAS is the generation of ensemble forcings [e.g., downwelling longwave (LW) and

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Hatim M. E. Geli, Christopher M. U. Neale, Doyle Watts, John Osterberg, Henk A. R. De Bruin, Wim Kohsiek, Robert T. Pack, and Lawrence E. Hipps

1. Introduction Scintillometer measurements of turbulence are used in hydrological, micrometeorological, agricultural, and water resources studies. Their importance and effectiveness rise from the ability to provide path-averaged and area-averaged estimates of sensible ( H ) and latent ( LE ) heat flux that cover large spatial scales. Depending on the type of instrument, these estimates could cover several kilometers ( Meijninger et al. 2002a , b ; Chehbouni et al. 1999 ) as compared to Bowen

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Mototaka Nakamura, Minoru Kadota, and Shozo Yamane

1. Introduction Attempts to understand the relationship between the extratropical mean flow and waves in the context of the general circulation have greatly benefited from the development of theoretical diagnostic tools that simplify the mathematical description of the relationship. The major tool of this kind first developed is the Eliassen–Palm (EP) flux ( Eliassen and Palm 1961 ; Andrews and McIntyre 1976 ). It describes, in the zonally averaged framework, the propagation characteristics of

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Jiping Liu, Judith A. Curry, Carol Anne Clayson, and Mark A. Bourassa

1. Introduction The thermodynamic disequilibrium between the tropical atmosphere and ocean provides an energy source for tropical cyclones (e.g., Kleinschmidt 1951 ; Emanuel 1986 ), arising primarily from the undersaturation of near-surface air. The dependence of the air–sea energy transfer rate on wind has been hypothesized to be the principal feedback mechanism that allows hurricanes to develop (e.g., Emanuel 2003 ). Hence, accurate knowledge of the latent heat flux across the air

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