A case study of the tropical Hot Event in November 2006 (HE0611) using a geostationary meteorological satellite and the TAO/TRITON mooring array

Abstract

Qin et al. have found Hot Events (HE), which are short‐term (about 20 days) large‐scale (about 15,000,000 km2) regions with very high Sea Surface Temperatures (SST > 30°C). Following their definition, an HE was identified in the tropical western Pacific in November 2006, which is named HE0611. A case study of HE is conducted by using the advanced satellite products and in‐situ measurements from the TAO/TRITON mooring array. Two parts (HE0611‐East and ‐West) with very high SST connected to form HE0611. SST in HE0611‐West increases quickly with large diurnal SST variations, which are caused by large solar radiation and suppressed latent heat loss. The increase of the mixed‐layer heat content is clearly accounted for the accumulated heat gain through the air‐sea interaction. The formation mechanism of HE0611‐East is completely different; its very high SST is supported by a subsurface high SST anomaly associated with the El Niño. Two phenomena similar to HE0611 were observed in November of the El Niño years of 1994 and 2002.

Climatology of hot events in the western equatorial Pacific

“…During HEs, latent heat release is suppressed, which in turn suppresses the surface evaporation process. Moreover, Qin et al (2008) and Kawamura (2009, 2010) found evidence of subsiding air during HEs. Hence, frequent HE occurrence may influence vapor transport through the large-scale circulation.…”

“…Over the course of 10 years (1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003), they identified 31 HEs distributed in the tropical oceans, with most of the HEs (68 %) detected in the western equatorial Pacific. This and subsequent studies concluded that the HEs occur when there are high levels of solar radiation and low wind speeds, and that HE development involves a high diurnal SST amplitude Qin et al 2007Qin et al , 2008Kawamura 2009, 2010). However, there are still some problems with their detection method.…”

“…However, there are still some problems with their detection method. Qin et al (2007) used a time-dependent SST threshold of approximately 30 °C to detect the HEs, and Qin et al (2008) used a fixed SST threshold of 30 °C. Both of these methods are affected by seasonal variation and may underestimate SST variations associated with HEs during the cold season.…”

Strong Ocean–Atmosphere Interactions during a Short-Term Hot Event over the Western Pacific Warm Pool in Response to El Niño

“…With an advent of remote sensing technologies through clouds, newgeneration satellites provide an improved monitoring of the ocean-atmosphere conditions at high resolutions (Wentz et al 2000). Based on satellite-derived daily SST, the large-scale phenomena of very high SST even with a short life cycle of 2-3 weeks can be well detected over the Indo-Pacific warm pool (Qin et al 2007). These high-SST events (here called hot events) have a shorter time scale and but larger area size than the hot spots defined by monthly SST in Waliser (1996).…”

“…Statistics of hot spots/events show that their occurrences probably respond to the influence from intraseasonal, seasonal, and interannual variability (Waliser 1996;Qin et al 2007). On the intraseasonal time scale, the evolution of hot spots particularly during TOGA COARE has been linked to the organized convection of the MJO Johnson et al 2001;Duvel and Vialard 2007).…”