CLIMATECLIMATE: CLIMATE A region’s long-term AVERAGE WEATHER conditions (usually based on data from the previous 30 years) Defined by two factors: TEMPERATURE patterns HUMIDITY (MOISTURE level)

TEMPERATURE Temperature patterns involve both AVERAGE Annual Temperature and Annual Temperature RANGE  Range = CHANGE in Temperature over the year

AVERAGE Annual Temperature  Either higher LATITUDE or higher ELEVATION results in LOWER AVERAGE temperature 24-hr Average Temperature Watertown, NY JanFebMarAprMayJunJulAugSepOctNovDec Yr °C °F

Classification: POLAR POLAR - HIGH latitudes, so always COLD TROPICAL TROPICAL - LOW latitudes, so always WARM MID–LATITUDE MID–LATITUDE (or SEASONAL) Annual Temperature RANGE depends on DISTANCE from a large body of water (the OCEAN, SEAS, or large LAKES) Temperature Range Distance from water

Classification: MARINE MARINE: NEAR a large body of water SMALLER Temperature RANGE, so Cooler SUMMERS and Warmer WINTERS CONTINENTAL CONTINENTAL: INLAND location GREATER Temperature RANGE, so Cooler WINTERS and Warmer SUMMERS

MARINE CONTINENTAL

Classification: HUMIDITY  Classification: HUMID / ARID

Climate classification of the General Brown School District  MID–LATITUDE HUMID MARINE Climate

GEOGRAPHIC FACTORS LARGE BODIES OF WATER  Coastal climates are more HUMID Coastal areas have a SMALLER Annual Temperature RANGE than INLAND areas, so COOLER Summers and WARMER Winters

MOUNTAIN RANGES  WINDWARD: the side of a range facing TOWARD incoming weather LEEWARD: the side facing AWAY FROM incoming weather OROGRAPHIC LIFTING

MOUNTAIN RANGES  Air masses rising over mountains release their MOISTURE on the WINDWARD side, so WINDWARD: COOL, HUMID, heavy PRECIPITATION, usually with RAIN FORESTS

MOUNTAIN RANGES  Air masses rising over mountains release their MOISTURE on the WINDWARD side, so WINDWARD: COOL, HUMID, heavy PRECIPITATION, usually with RAIN FORESTS LEEWARD: WARM, DRY (ARID), often with DESERTS

CITIES  TEMPERATURES are HIGHER than in surrounding areas

CITIES  TEMPERATURES are HIGHER than in surrounding areas WHY? Manmade materials replacing Natural materials - Lower Specific Heat - Darker colors Burning of Fossil Fuels produces Heat and releases Carbon Dioxide, a Greenhouse Gas Fewer Trees to shade the ground

WINDWARD Humid Cool Rain Forests LEEWARD Arid Warm Deserts MOUNTAINRANGES

CLIMATE and MOISTURE The moisture level of a region’s CLIMATE depends on the balance between: NEED for moisture for natural processes and available moisture SUPPLY NEED for moisture is determined solely by TEMPERATURE, so moisture NEED varies with LOCATION (that is, LATITUDE and ELEVATION) and with the SEASON A region’s moisture SUPPLY comes from PRECIPITATION

An area has a HUMID climate if moisture SUPPLY is greater than the NEED for moisture An area has an ARID climate if the NEED for moisture is greater than the moisture SUPPLY SURPLUS SURPLUS: Moisture SUPPLY greater than moisture NEED DEFICIT: Moisture NEED greater than moisture SUPPLY

In MID–LATITUDE HUMID climates (as in NEW YORK), since moisture NEED depends on TEMPERATURE, there is a SEASONAL variation in moisture conditions

HIGH temperatures in SUMMER result in HIGH need and DEFICIT LOW temperatures in WINTER result in LOW need and SURPLUS, which reaches a MAXIMUM at the time of the the SPRING THAW

COASTAL WIND PATTERNS COASTAL WIND PATTERNS Along an OCEAN COAST or a LAKESHORE: DAY During the DAY, LAND WARMS more rapidly, so the warmer air above the LAND (with LOWER pressure) RISES, cooler the cooler air above the WATER (with HIGHER pressure) SINKS, and wind blows toward the LAND  ONSHORE Breeze

At NIGHT, LAND COOLS more rapidly, so the warmer air above the WATER (with LOWER pressure) RISES, the cooler air above the LAND (with HIGHER pressure) SINKS, and wind blows toward the WATER  OFFSHORE Breeze

VERTICAL AIR MOVEMENTS RISING Air Masses, found at FRONTS, along the WINDWARD side of MOUNTAINS, or at CONVERGENCE ZONES (see below) EXPAND as PRESSURE at higher altitudes DECREASES Since no ENERGY is being added, the air mass uses its own ENERGY to EXPAND, and the E X P A N S I O N causes COOLING COOLING of the RISING air

DESCENDING Air Masses as PRESSURE INCREASES and the air is COMPRESSED, release the ENERGY absorbed during EXPANSION, so the COMPRESSION causes WARMING WARMING of the DESCENDING air

WINDWARD LEEWARD Cooling from Expansion of Rising Air Warming from Compression of Sinking Air

AAAA TTTT MMMM OOOO SSSS PPPP HHHH EEEE RRRR IIII CCCC C C C C IIII RRRR CCCC UUUU LLLL AAAA TTTT IIII OOOO NNNN There is a large-scale, permanent circulation pattern within Earth’s Atmosphere, resulting from the process of CONVECTION, and caused by UNEQUAL HEATING of the ATMOSPHERE due to Earth’s SPHERICAL shape and the differing ANGLES of INSOLATION across the surface which result 

The WARMEST air, along the EQUATOR, RISES, while the COLDEST air, at the POLES, SINKS toward Earth’s surface, but the circulation pattern between the EQUATOR and the POLES is affected by Earth’s ROTATION and the CORIOLIS EFFECT

As a result  THREE CONVECTION Cells circulate between the EQUATOR and each POLE

At the BOUNDARIES between the Cells: CONVERGENCE Zone CONVERGENCE Zone: ( at the EQUATOR + 60º Latitude ) RISING WARM Air causes a flow COUNTERCLOCKWISE INWARD TOWARD the Zone, producing a Band of LOW Pressure and a WARM, HUMID Climate (RAIN FORESTS)

At the BOUNDARIES between the Cells: DIVERGENCE Zone DIVERGENCE Zone: (30º Latitude + the POLES) SINKING COOL Air causes a flow CLOCKWISE OUTWARD AWAY FROM the Zone, producing a Band of HIGH Pressure and a COOL, ARID Climate (DESERTS)

0º 30º N Convection Cell Convection Cell Convection Cell New York LOW Pressure HIGH Pressure DIVERGENCE Zone CONVERGENCE Zone

Equator 30º N

LOW Pressure LOW Pressure LOW Pressure HIGH Pressure HIGH Pressure HIGH Pressure HIGH Pressure

Between the CONVERGENCE and DIVERGENCE Zones, a series of PLANETARY WIND BELTS determine the general flow of air and the movement of WEATHER SYSTEMS across Earth’s surface

PREVAILING Winds: Flow is From DIVERGENCE Zones (HIGH Pressure) To CONVERGENCE Zones (LOW Pressure), but CURVING due to the CORIOLIS EFFECT In North America  Flow from the SOUTH (DIVERGENCE Zone at 30º North) turns to the RIGHT, creating the PREVAILING WESTERLIES

Planetary Wind Belts

The positions of the ZONES and WIND BELTS change with the SEASONS  In SPRING and SUMMER, there is a NORTHWARD shift, as the SUN’S LATITUDE moves NORTH of the EQUATOR As a result, during these seasons the TRADE WINDS (PREVAILING EASTERLIES) move TROPICAL STORMS and HURRICANES toward the SOUTHEASTERN UNITED STATES from the TROPICAL ATLANTIC OCEAN (the reason there is a “HURRICANE SEASON”)

OCEAN CURRENTS  ocean exchanges heat with the overlying atmosphere  currents determined by global winds currents determined by global windsESRT

El Nino / La Nina