Climate and atmospheric dynamics: climate types and climatic elements
Domain 2 separates climatic elements (what you measure) from climatic factors (why they vary), and then asks you to explain the atmospheric machinery that produces the Castilian climate.
Elements and factors
- Elements: temperature, precipitation, pressure, wind, humidity, insolation and evapotranspiration.
- Factors: latitude (36–43° N, under the westerlies), altitude (about 0.6 °C per 100 m), distance from the sea, relief and ocean currents.
- The Cantabrian Range acts as a barrier: the north face intercepts Atlantic fronts, the southern slope receives drier descending air.
Atmospheric dynamics
- Winter: the polar front and jet stream shift south; Atlantic fronts arrive from the west and south-west, followed by cold northerly advection that produces frost.
- Summer: the Azores High extends over Iberia, producing subsidence, clear skies and a pronounced drought; a shallow thermal low forms over the Peninsula.
- Autumn: cold air aloft over a still-warm Mediterranean generates DANA situations, with intense rainfall concentrated on the Mediterranean coast.
- NAO: a positive phase strengthens the westerlies and gives wetter winters in the north-west.
Castilla y León
Continental Mediterranean: 400–600 mm of annual precipitation falling away from north-west to south-east, two to three arid summer months, January means of 3–4 °C, July means of 20–22 °C, a frost period from November to April, diurnal ranges above 15 °C and about 2 400 hours of sunshine. Mountain fringes exceed 1 000 mm. Aridity is measured with Gaussen (arid when P mm < 2T °C), Martonne and Lautensach–Mayer indices.
Worked example
A station records June 18 °C and 30 mm, July 21 °C and 15 mm, August 20 °C and 20 mm, May 14 °C and 50 mm. Apply P < 2T: June 36 > 30 (arid), July 42 > 15 (arid), August 40 > 20 (arid), May 28 < 50 (humid). Three arid months, a summer minimum and spring–autumn maxima define a continental Mediterranean regime, not an Atlantic one.
Traps
- Calling the whole region Atlantic: only the north-west fringe is.
- Confusing continentality with altitude as an explanation of thermal range.
- Placing the Azores High in winter instead of summer.
- Forgetting that total precipitation decreases inland and southwards.