Cloud-radiative impacts on the tropical Indian Ocean associated with the evolution of 'monsoon breaks'

A detailed diagnostic analysis of a suite of observed datasets was carried out with a view to understand the importance of cloud-radiative effects on the evolution of prolonged 'monsoon breaks' over the Indian region. The study particularly focuses on the role of clouds in affecting the sub-seasonal/intra-seasonal variability of sea surface temperature (SST) and atmospheric convection in the equatorial and south-eastern tropical Indian Ocean (SETIO) during monsoon-break transitions. A characteristic feature of the monsoon-break evolution is the appearance of suppressed convection over the SETIO region nearly 7-10 days prior to the commencement of a break spell over India. It is seen from the present analysis that the lack of cloud cover over the SETIO during the 'pre-break' phase leads to significant warming of the tropical Indian Ocean due to strong solar insolation at the surface. During the 'pre-break' phase, the net cloud-radiative forcing (NETCRF) at the surface is found to be typically around -30 Wm-2 and the mean SST in the SETIO is about 29.3°C. Following the transition to a monsoon-break phase, the cloud amount increases by about 25 over the SETIO region in association with intensified convection. The NETCRF at the surface over the SETIO averaged during the 'break' phase is found to be about -60 Wm-2 (i.e. a change of about -30 Wm-2 from the 'pre-break' phase). Consistent with the above change in the NETCRF, the SST in the SETIO shows a cooling of about 0.7°C, although the mean SSTs during the 'break' phase remain as high as 28.6°C. On the basis of the findings from this study, it is suggested that the SST warming during the 'pre-break' phase plays a key role in maintaining high SST and allows sustained convection to occur over the SETTO during prolonged monsoon breaks

Observed mini-cold pool off the southern tip of India and its intrusion into the south central Bay of Bengal during summer monsoon season

The observed mini-cold pool (MCP) off the southern tip of India (STI) and its intrusion into the south central Bay of Bengal (BoB) during the summer monsoon season is examined utilizing the available satellite and in situ measurements. The mechanisms that govern the occurrence of this MCP through surface wind field and its curl, net surface heat flux and divergence in the near-surface circulation (Ekman + geostrophic) are examined. The observed MCP primarily appears to be driven by the upwelling caused by the divergence in the near-surface circulation. The upwelling results in both shoaling of thermocline and enhanced blooming of chlorophyll-a. With the progress of the season the sea surface temperature (SST) cooling associated with MCP intrudes into the south central BoB by the Summer Monsoon Current (SMC). Copyright 2006 by the American Geophysical Union

Observed intraseasonal variability of mini-cold pool off the southern tip of India and its intrusion into the south central Bay of Bengal during summer monsoon season

The observed evolution of a mini-cold pool (MCP) off the southern tip of India (STI) and its intrusion into the south central Bay of Bengal (BoB) during the summer monsoon season shows pronounced cooling episodes on intraseasonal time scale with differences in their number, intensity, duration and spatial extent. This variability that changes from year to year appears to be primarily determined by the corresponding variability in the upwelling driven by the divergence in the near-surface (Ekman + geostrophic) circulation and wind induced mixing. The signature of this cooling carried by the Summer Monsoon Current (SMC) is seen with reduction in intensity in the south central BoB limited mostly only to south of about 10°N. In the background of slow cooling caused by SMC, the cooling episodes of different amplitudes occur in the south central BoB suggesting that spatially variable wind forcing is responsible for producing these episodes simultaneously on intraseasonal time scale

Development of a mnemonic screening tool for identifying subjects with Hunter syndrome

The Hunter Outcome Survey (HOS), an international, long-term observational registry of patients with Hunter syndrome, was used to develop a simple mnemonic screening tool (HUNTER) to aid in the diagnosis of Hunter syndrome. Data regarding the prediagnosis prevalence of ten specific signs and symptoms present in individual patients enrolled in the HOS were used to develop the HUNTER mnemonic screening tool. A total score of 6 or greater using a weighting scheme in which certain manifestations were assigned a weight of 2 (facial dysmorphism, nasal obstruction or rhinorrhea, enlarged tongue, enlarged liver, enlarged spleen, joint stiffness) and others assigned a weight of 1 (hernia, hearing impairment, enlarged tonsils, airway obstruction or sleep apnea) correctly identified 95 % of patients who had no family history of Hunter syndrome or who were not diagnosed prenatally. No association between age at diagnosis and HUNTER score was found. Conclusion: The HUNTER mnemonic appears to be a useful screening tool. Further validation in the clinical setting will be necessary to confirm its utility