High sea ice production (SIP) generates high-salinity water, thus, influencing the global thermohaline circulation. Estimation from passive microwave data and heat flux models have indicated that the Ross Ice Shelf polynya (RISP) may be the highest SIP region in the Southern Oceans. However, the coarse spatial resolution of passive microwave data limited the accuracy of these estimates. The Sentinel-1 Synthetic Aperture Radar dataset with high spatial and temporal resolution provides an unprecedented opportunity to more accurately distinguish both polynya area/extent and occurrence. In this study, the SIPs of RISP and McMurdo Sound polynya (MSP) from 1 March–30 November 2017 and 2018 are calculated based on Sentinel-1 SAR data (for area/extent) and AMSR2 data (for ice thickness). The results show that the wind-driven polynyas in these two years occurred from the middle of March to the middle of November, and the occurrence frequency in 2017 was 90, less than 114 in 2018. However, the annual mean cumulative SIP area and volume in 2017 were similar to (or slightly larger than) those in 2018. The average annual cumulative polynya area and ice volume of these two years were 1,040,213 km2 and 184 km3 for the RSIP, and 90,505 km2 and 16 km3more »
LYCODON ALCALAI (Alcala’s Wolf Snake). DIET.
Lycodon alcalai is a small, terrestrial snake endemic to the northern Philippines where it is known from the islands of Batan (70 km2), Sabtang (16 km2), and Calayan (196 km2; Ota and Ross 1994. Copeia 1994:159–174; Oliveros et al. 2011. Sci. Pap. Nat. Hist. Mus. Univ. Kans. 43:1–20). Although L. alcalai has been reported to prey upon Common Tree Frogs (Polypedates leucomystax) and unidentified, soft-shelled reptilian eggs (Ota and Ross 1994, op. cit.), little natural history information is available for this species. Here, we report on a new diet item for L. alcalai: an as of yet undescribed species of scaly-toed gecko (Lepidodactylus).
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