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-Do cirrus clouds (resulting from the El Nino warming)cause a net radiative heating or cooling of the upper troposphere?
-At the ocean surface, what are the relative magnitudes of cooling be cirrus shortwave cloud forcing and warming by the greenhouse effect of increased water vapor and clouds.

Diabatic forcing of the tropical upper troposphere (10-18km): The potential temperature increases with altitude above 5 km, which requires a major heat source within the upper troposphere. Tropical meteorologists have assumed that the latent heat released by penetrating cumulonimbus clouds can account for the required heat source. GCM sensitivity studies have revealed that IR and solar radiative heating within cirrus anvils can completely account for the required heat source. We need divergence of IR and solar radiation from about 10-20 km in the equatorial Pacific west of the date line, and simultaneous measurements of water vapor, radiatively active gases, and visible optical depth of the cirrus.
-What processes determine the tropopause height and the lapse-rate of the atmosphere?
-How is the advective cell structure of the tropopause and the lower stratosphere related to the tropopause height? How is this in turn related to the equator-to-pole heat flux?
-How important is the absorption of IR radiation in the window region by optically thin cirrus to the heat budget of the upper troposphere and tropopause region?

Improved Parameterization of Cloud Feedback in GCMs
Vertical distribution of diabatic forcing: One of the fundamental uncertainties is the vertical distribution of the cloud radiative forcing and the latent heating. GCMs currently rely entirely on convection models, intuition and ad-hoc schemes to simulate these fields that are the fundamental forcing terms of the general circulation.
-What is the link, if any, between the large-scale convergence of moisture and the altitude of deep convective clouds?
-What is the link between the altitude of deep convective clouds and cirrus cloud altitudes?
-What microphysical processes dictate the structure of individual convection events?
-What processes characterize the ice particle size distribution in cirrus? Does it vary appreciably with altitude of cirrus?

Calibration and Interpretation of Satellite Measurements
Angular distribution of solar and IR radiation at tropopause altitudes: In order to estimate fluxes and heating rates, we need the angular distribution of the radiation. Satellites measure radiation from one angle and use elaborate models (requiring computer codes tens of thousands of lines long). Even after three decades of work, this problem has not been solved and is the fundamental source of uncertainty in all radiation budget measurements.
-What is the relationship between Top of the Atmosphere fluxes (observed by satellite) and tropopause fluxes (which are the fundamental quantities needed to estimate the climate forcing terms)?
-It would be of great scientific interest to examine how the cloud-radiative forcing changes in magnitude and perhaps in sign between the total band (0.2-5 mm) and the near-IR spectral regions.