Arctic and Antarctic Sea Ice

The US National Snow and Ice Data Center has reported on 27th September that Arctic sea ice appears to have reached its annual minimum extent on 19th September. On that day it covered an area of 4.60 million square kilometers (1.78 million square miles). This year’s minimum was the third-lowest in the satellite record, after … Continue reading “Arctic and Antarctic Sea Ice”

Fujiwhara Effect

The Fujiwhara effect describes the rotation of two storms around each other. It’s most common with tropical cyclones but also occurs in other cases. A good way to picture this is to think of two ice skaters who skate quickly towards each other, nearly on a collision course, grab hands as they are about to … Continue reading “Fujiwhara Effect”

Measuring fluxes on Arran

We measured the radiation and turbulent flux densities during the fieldtrip – Rn is net radiation, G is ground heat flux, H is sensible heat flux and LE is latent heat flux.The graph shows data for our sunniest day, 8th September 2010.The open symbols are the measurements, and the lines are predictions using the Penman-Monteith … Continue reading “Measuring fluxes on Arran”

Arran field course – live blog – Saturday 11th September

Our final day on Arran and our final occluded fronts from the dominant series of systems influencing our weather look to have passed during mid-morning. Yesterday (Friday 10th) we saw a really nice frontal progression in our weather station measurements as another occluded front passed around 10:30 local time. The transition in air mass was … Continue reading “Arran field course – live blog – Saturday 11th September”

Arran field course – live blog – Thursday 9th September

Two more days on Arran with some glorious early autumn sunshine in addition to our typical mix of cloudy and shower weather. A sequence of our 12Z radiosonde soundings from Tuesday to today (incorporated intothe Met Office observation processing suite) shows this fluctuating picture of air masses which we have observed On Tuesday, Arran was … Continue reading “Arran field course – live blog – Thursday 9th September”

Arran field course – live blog – Tuesday 7th September

Today’s activity for all groups was an instrumented walk up Goat Fell (850m above sea level) the highest point on Arran. We left the field centre with some trepidation, expecting heavy rainfall all day. Rain began for us around 2300 local time last night as the occluded front associated with the complex low to our … Continue reading “Arran field course – live blog – Tuesday 7th September”

Arran field course – live blog – Monday 6th September

This week 12 BSc and MMet students from Reading, along with 5 staff and 36 students and staff from the University of Leeds are here in Lochranza on Arran for a weeklong residential field course. The students will be involved in various activities including a hill walk, radiosonde and ozonesonde launches, boundary layer sampling with … Continue reading “Arran field course – live blog – Monday 6th September”

Tropical Parade in the Atlantic

While most of the attention is focused on Hurricane Earl, tropical storms Fiona and Gaston (and a strong tropical wave off Africa) complete the tropical parade in the Atlantic. As of 12:00 UTC, Hurricane Earl was located about 355 miles (575km) south of Cape Hatteras. Earl has maximum sustained winds of 145mph (230kph) as it … Continue reading “Tropical Parade in the Atlantic”

Hurricane Earl and Tropical Storm Fiona

Earl is a powerful Category 3 hurricane now located northeast of the Bahamas. As of 9:00 a.m., UTC, Hurricane Earl was located at 24.0°N, 71.2°W, or 175 miles (280km) north of Grand Turk Island and 815 miles (1315km) south-southeast of Cape Hatteras, North Carolina with maximum sustained winds of 125mph (205kph). Earl is moving to … Continue reading “Hurricane Earl and Tropical Storm Fiona”