A Parameter Study of Interactions Between Convective Clouds, the Convective Boundary Layer, and a Forested Surface

Garrett, Alfred J.

doi:10.1175/1520-0493(1982)110<1041:apsoib>2.0.co;2

Cited by 60 publications

(30 citation statements)

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“…The simulations mimic the conditions during convectively active flat-pressure synoptic situations, which may persist over several days in midlatitude regions, as for example in July 2006 over mid Europe (Hohenegger et al, 2008) or in summertime in the southeastern USA (Garrett, 1982). Sensitivity of precipitation to soil moisture appears to be large in such conditions.…”

Section: Copyright C 2012 Royal Meteorological Societymentioning

confidence: 98%

Diurnal equilibrium convection and land surface–atmosphere interactions in an idealized cloud‐resolving model

Schlemmer

Hohenegger

Schmidli

et al. 2012

Quart J Royal Meteoro Soc

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The influence of soil moisture and atmospheric stability on mid-latitude diurnal convection and land-atmosphere exchange is investigated in an idealized cloudresolving modelling framework using a full set of parametrization schemes. In each member of a series of month-long experiments, the model attains a state where deep, precipitating convection is triggered every day. This state is referred to as equilibrium diurnal convection. The triggering occurs via different mechanisms depending on the atmosphere-soil setting. In our framework latent heat fluxes comprise the primary control over the precipitation amounts. We find that evaporation is regulated by the availability of energy on the one hand and the availability of soil moisture and the near-surface saturation deficit of the atmosphere on the other. Increased cloud cover over wet soils reduces net short-wave radiation but increases net long-wave radiation, leading to a near-compensation of the two effects on available energy. Increased boundary layer moisture is removed by deep convection, thus increasing the near-surface saturation deficit and preventing a negative feedback of boundary layer moisture content on the latent heat fluxes. We also find that there is a spatial correlation between soil moisture and precipitation anomalies, suggesting that the soil moisture precipitation feedback acts on a scale of 10-50 km. Copyright c 2012 Royal Meteorological Society Key Words: convection; cloud-resolving modelling; land-surface atmosphere interactions

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Section: Copyright C 2012 Royal Meteorological Societymentioning

confidence: 98%

Diurnal equilibrium convection and land surface–atmosphere interactions in an idealized cloud‐resolving model

Schlemmer

Hohenegger

Schmidli

et al. 2012

Quart J Royal Meteoro Soc

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show abstract

“…The tropics are also important sources and sinks of chemical species critical to climate change impacts (Hewitt et al, 2009). Garrett (1982) presented an atmospheric model structured in such a way as to enable the convective boundary layer and convective cloud formation over a forested surface to be studied. It was stressed that the soil moisture content, the canopy density and the surface roughness were likely to influence the daily growth and decay of the boundary layer and the formation of convective clouds.…”

Section: The Tropical Boundary Layermentioning

confidence: 99%

Remote sensing of the tropical rain forest boundary layer using pulsed Doppler lidar

2010

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Abstract. Within the framework of the Natural Environment Research Council (NERC) Oxidant and Particle Photochemical Processes (OP3) project, a pulsed Doppler lidar was deployed for a 3 month period in the tropical rain forest of Borneo to remotely monitor vertical and horizontal transport, aerosol distributions and clouds in the lower levels of the atmosphere. The Doppler velocity measurements reported here directly observe the mixing process and it is suggested that this is the most appropriate methodology to use in analysing the dispersion of canopy sourced species into the lower atmosphere. These data are presented with a view to elucidating the scales and structures of the transport processes, which effect the chemical and particulate concentrations in and above the forest canopy, for applications in the parameterisation of climate models.

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“…Nevertheless, we believe this approach is meaningful to observe the basic behavior of cumulus convection over land and related feedback processes if some essential features of the real atmosphere are reproduced in the modeled equilibrium atmosphere. Moreover, such situations free from synoptic disturbances often appear in midsummer over continents, such as the southeastern United States, influenced by the subtropical high [Garrett, 1982].…”

Section: Experimental Designmentioning

confidence: 99%

The interaction of cumulus convection with soil moisture distribution: An idealized simulation

Emori¹

1998

J. Geophys. Res.

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Abstract. In order to investigate the interaction between cumulus convection and soil moisture distribution, two-dimensional numerical experiments using a regional atmospheric model are performed. The model roughly resolves each convective cell and represents cloud processes by a microphysics parameterization. Two long-term (60-day) integrations with relatively dry and wet conditions are made with the atmosphere-land system in a quasi-equilibrium state. Though the initial and boundary conditions are horizontally homogeneous, horizontal contrasts in soil moisture spontaneously develop due to the spotty nature of convective precipitation. When intense soil moisture contrasts develop, they cause surface temperature contrasts through a change in evaporation. As a result, thermally induced local circulations occur in the daytime, with upward branches over the dry and hot regions and downward branches over the wet and cool regions. Most cumulus convection events are initiated by the upward motion of this local circulation over the dry region. They mostly occur in the afternoon (1300-1700 LT), while convection that forms over regions that are wet throughout may occur at any time during the day. The intense precipitation over the dry region "overdamps" the soil moisture contrast, which results in the maintenance of a heterogeneous distribution of soil moisture. IntroductionThe influence of land-surface processes on precipitation on both a global and local scale has been intensively discussed in recent years. As reviewed by Mintz

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A Parameter Study of Interactions Between Convective Clouds, the Convective Boundary Layer, and a Forested Surface

Cited by 60 publications

References 0 publications

Diurnal equilibrium convection and land surface–atmosphere interactions in an idealized cloud‐resolving model

Diurnal equilibrium convection and land surface–atmosphere interactions in an idealized cloud‐resolving model

Remote sensing of the tropical rain forest boundary layer using pulsed Doppler lidar

The interaction of cumulus convection with soil moisture distribution: An idealized simulation

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