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Unique sets of Electra Doppler Radar (ELDORA) observations in both developing and nondeveloping tropical disturbances in the western North Pacific are used to retrieve latent heating and cooling rates. During the reintensification of Sinlaku, maximum heating rates of about 80 K h 21 are diagnosed in the upper troposphere in the region of a strong updraft and maximum cooling rates of about 245 K h 21 are diagnosed in the lower troposphere in the region of a strong convective-scale downdraft. The southern convective burst in the pre-Nuri mission had a lower-tropospheric maximum in latent heating that was a more favorable condition for tropical cyclone formation than was the upper-tropospheric maximum in heating and the lowertropospheric maximum in cooling in the northern convective burst. Two nondeveloping tropical disturbances had deeper layers of more uniform heating and of cooling rates, and some evidence of more shallow cloud tops, that distinguished them from the developing cases. Although the Shige et al. Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) algorithm was only intended to be applied over large areas on longer time scales, the PR-derived latent heating profiles were compared with the ELDORA-derived profiles to reveal important mesoscale effects. Because all six cases indicated near-zero cooling rates, a new TRMM PR algorithm should be developed that would include the effects of saturated convective-scale downdrafts in tropical mesoscale convective systems (MCSs). Production of a legacy TRMM PR dataset with this improvement would be useful for diagnosing tropical cyclone formation dating back to 1998, and for specifying initial and validation conditions for numerical models in the tropics.

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[1] The diurnal variations in summer rainfall over the South China Sea (110°EÀ120°E, 10°NÀ20°N) are examined for active and inactive intraseasonal oscillation (ISO) periods that are characterized by strong and weak 850-hPa zonal winds, respectively. By analyzing the rainfall retrievals from the Tropical Rainfall Measuring Mission Precipitation Radar for the period 1999 -2006, it is found that the peak rainfall during the active and inactive ISO periods occurs in the late morning and late evening, respectively. The morning peak in the active ISO period arises from the organized oceanic convective systems associated with the local convergence along the west coast of the Philippines. The evening peak in the inactive ISO period originates from a stratiform morphology that is initiated by land-based convective systems owing to the increased thermodynamic instability over the Philippines during daytime. Citation: