Wednesday, May 25, 2011

2010-11 accumulation

Snow accumulation on Quelccaya has ended in recent years by the second half of May. In some years (e.g., 2005, 2006, 2010), peak accumulation was reached during April. Only in 2009 was there a minor snowfall event after mid-May.

The pattern of accumulation this year has exactly paralleled the other La Niña year (2008) since late April, with one snowfall event of ~20 cm during the second week of May. In terms of snow depth, this year saw only ~10 cm less accumulation than 2008 and ranks second since our measurements began in 2003.

Planning is underway for fieldwork in early July. At this time detailed density and temperature profiles will be made at the weather station, which will determine accumulation for the year in more meaningful terms of water equivalence. We also hope to dig one or more snowpits upwind of the AWS to assess any precipitation gradient on the ice cap. Most importantly, this fieldwork will recover the first high-accuracy humidity measurements made at any high-elevation AWS. These 5-minute interval measurements began on 3 June last year, so now span an entire year.

Fieldwork for 2011 will also include several interesting and potentially very valuable collaborations, looking into the isotopic composition of water vapor, ice volume changes over the past 25+ years, and avian ecology. Stay tuned!