Diurnal cycle of the South Pacific Convergence Zone in 30 years of satellite images

Abstract

A data set of three-hourly South Pacific Convergence Zone (SPCZ) location and extent, from which IR temperature within the SPCZ may be obtained, for 1980-2012, November-April is used to examine the diurnal cycle of the SPCZ. Maximum SPCZ area occurs at 15:00-18:00 local standard time (LST). Two minima in mean IR temperature are evident, one at 13:00-16:00 LST, nearly coinciding with the maximum in area, and the second in the early morning hours at 05:00-07:00 LST, when area is at a minimum. The morning minimum in mean IR temperature is associated with a peak in deep convection while the afternoon minimum is associated with a peak in midlevel clouds. On average, the morning minimum in IR temperature dominates in the tropical regions of the SPCZ, while the afternoon IR temperature minimum dominates in the subtropical regions of the SPCZ. The relative strength of the two IR temperature minima is affected by the seasonal cycle, intraseasonal variability associated with active Madden Julian Oscillation events, and interannual variability due to the El Niño Southern Oscillation. The morning IR temperature minimum becomes more dominant when the SPCZ is more frequently present or when the SPCZ is shifted toward the equator. In terms of cloud height, midlevel clouds dominate at all times in all regions of the SPCZ and peak in abundance between 15:00-18:00 LST. Low-level clouds peak near midnight and then transition to high-level clouds, which peak between 03

Characteristics of Diurnal Pulses Observed in Typhoon Atsani Using Retrieved Cloud Property Data

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Sensitivity of Landsat 8 Surface Temperature Estimates to Atmospheric Profile Data: A Study Using MODTRAN in Dryland Irrigated Systems

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“…Apart from being a fundamental variable in quantifying elements of the surface energy budget [1], LST has been used to study ocean-atmosphere interactions [2], to track global warming and climate change impacts [3,4], as well as being widely used in studies of vegetation monitoring [5], drought persistence [6] and urban climate assessments [7]. LST also plays a critical role in linking the water and energy cycles through its relationship with surface heat fluxes [8].…”

A Multivariate Probabilistic Framework for Tracking the Intertropical Convergence Zone: Analysis of Recent Climatology and Past Trends

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