Reflection #1

Source: http://travel.yahoo.com/p-travelguide-191502077-lima_vacations-i

Source: http://www.trekearth.com/gallery/Europe/United_Kingdom/England/Cambridgeshire/Cambridge/photo39353.htm

For the first reflection assignment, I will compare the weather and climate of Cambridge, England with that of Lima, Peru. Cambridge has a maritime climate while Lima a subtropical and desert climate. Lima has consistently mild weather throughout the year and receives little rainfall. The average low temperature in Lima is between 12°C and 18°C and the average high temperature in Lima is between 24°C and 28°C. Humidity within Lima is high and produces fast-dissipating morning fogs from December to April and continuous low-lying clouds and mist from May to November. Summers (Dec. to Apr.) in Peru's capital are warm and moist while winters (May to Nov.) are cool, damp, and cloudy. Lima is located on the coast of Peru, in the arid plains region to the west of the Andes mountains. A cold current, called the Humboldt current, travels along the coast of Peru and moderates the heat of Lima while also providing humidity and mist. The Andes mountains located to the east of Lima protect the capital city from the tropical climate and the storms formed in the Amazon Basin.

Average Temperature, Humidity, and Rainfall of Lima:

Source: http://www.limaeasy.com/lima_info/weather_in_lima_peru.php

Like Cambridge, Lima's climate is affected by nearby mountains. Both cities receive less rain than expected in their respective locations because local mountain ranges protect them from precipitation that is affecting nearby areas. Cambridge, however, receives significantly more rain annually than does Lima. Since both cities are near the ocean, their weather is impacted by currents running along the coasts. Cambridge's weather is largely dictated by the Gulf Stream while Lima's weather is dictated by the Humboldt Current. Though the Gulf Stream is a warm-water current and the Humboldt Current is a cold-water current, they both have the same effect on the two cities: the currents result in a more mild and consistent climate than is expected for the cities' locations. As a result, Lima has a cooler climate than would be expected and Cambridge has a warmer climate than would be expected. One major difference between the climate of Cambridge and that of Lima is the effect of El Niño. While Cambridge does not feel the impacts of an El Niño year, Lima experiences more rain than normal. 

Lima experiences only two seasons, winter and summer, while Cambridge enjoys the full spectrum of all four seasons. Because Lima is in the southern hemisphere, its seasons are reversed when compared to those of Cambridge. Winter in Lima occurs from May to November and summer occurs from December to April. So, while Cambridge is enjoying warm and clear summer days, Lima is trudging through an overcast and damp winter.

Blog Post #2

 Source: http://www.weatheronline.co.uk/reports/wxfacts/Air-masses-and-their-sources.htm

The United Kingdom, including Cambridge, is affected by five air masses: mT, cT, mP, cP, and A. In addition, it is affected by what is called Returning mP which is polar air that has moved south over the ocean and then returned northward to approach the U.K. from the south.

The Tropical Continental air mass originates in North Africa and approaches the U.K. from the southeast. This air tends to be dry and brings hot temperatures accompanied by clear skies in the summer. Sometimes, the air picks up moisture as it travels over the Mediterranean Sea and can result in thunderstorms.

The Tropical Maritime air mass originates in the subtropical Atlantic Ocean and approaches the U.K. from the southwest. While the air cools on its journey over the ocean, it loses little moisture. Thus, when it reaches the U.K. it brings warm, wet and overcast weather. In the summer, the clouds over Cambridge often burn off and the result is warmer and drier weather.

The Maritime Polar air originates over the Canadian arctic or the Greenland region and reaches the British Isles from the west or northwest. As the cold air mass travels over the ocean, it warms up from below and becomes unstable. Thus, the polar maritime air brings cool, moist air accompanied by rain and showers. Because Cambridge is sheltered by the Scottish and Welsh mountains, however, it remains drier than the rest of the island. In the spring and summer, the clouds heat up during the day. This results in showers and thunderstorms that can occur anywhere, including Cambridge. In winter, the showers are generally limited to the west coast.

The Arctic air mass generally only affects the U.K. in winter and is colder and drier than the Maritime Polar air. As it moves toward the British Isles, it accumulates enough moisture to generate sleet and snow. Cambridge is far enough south that it is usually not impacted by these showers and instead experiences cold weather with clear skies.

The Polar Continental air originates in Scandinavia or Russia and approaches the U.K. from the east or northeast. These air masses usually only affect the island during winter. This air causes below average temperatures in winter and above average temperatures in summer. The air is generally dry, resulting in fine and sunny weather. If the air mass passes over the North Sea between Denmark and Scotland, it gathers more moisture and brings cloudy weather to Cambridge, sometimes accompanied by drizzle or light snow.

Forecast for April 5, 2012 - April 8, 2012:

Source: http://www.metoffice.gov.uk/weather/uk/uk_forecast_pressure.html

Pressure chart symbols

	Cold front The leading edge of an advancing colder air mass. Its passage is usually marked by cloud and precipitation, followed by a drop in temperature and/or humidity.
	Warm front The leading edge of an advancing warmer air mass, the passage of which commonly brings cloud and precipitation followed by increasing temperature and/or humidity.
	Occluded front (or 'occlusion') Occlusions form when the cold front of a depression catches up with the warm front, lifting the warm air between the fronts into a narrow wedge above the surface. Occluded fronts bring cloud and precipitation.
	Developing cold/warm front (frontogenesis) Represents a front that is forming due to increase in temperature gradient at the surface.
	Weakening cold/warm front (frontolysis) Represents a front that is losing its identity, usually due to rising pressure. Cloud and precipitation becomes increasingly fragmented.

 Source: http://www.metoffice.gov.uk/weather/uk/uk_forecast_pressure.html

Cambridge is affected by cold fronts, arm fronts, and occluded fronts. By Saturday April 7, a warm front will have passed through Cambridge from the northwest, followed by a cold front approaching from the northeast. That cold front will then be followed by another warm front coming from the northwest by Sunday April 8. For Friday April 6 and Saturday April 7, Cambridge is expecting cloudy skies with relatively good visibility. By Sunday, however, there will be showers brought on by the arrival of the second warm front.

Cambridge lies in the eastern plains of England on the lee side of the Scottish and Welsh mountains. Since the maritime air masses approach the U.K. from the west and the continental air masses approach the U.K. from the east, Cambridge is typically drier than the majority of the island. The wetter air of the maritime air masses must pass over the mountains before reaching Cambridge, causing a slight rain shadow effect, while the drier air of the continental air masses approaches Cambridge directly. In general, Cambridge doesn't experience severe weather such as hurricanes or tornadoes. Instead, the weather remains fairly consistent throughout the year.

References:

http://www.metlink.org/weather-climate-resources-teachers/key-stages-weather-climate/key-stage-4-weather/ks4-airmasses-2.html