Monsoons

• A seasonally varying wind

• Created by a continental scale sea breeze

• Famously, the NE & SW Monsoons over the

Indian subcontinent

• Other monsoons exist (American monsoon)

• Seasonal monsoon winds change circulation

in the Indian Ocean (Somali Curent)

Sea Breezes

Sea Breezes

Monsoon Processes

Monsoon Processes

Summer Winter

SW Monsoon NE Monsoon

Monsoon Winds

SW Monsoon NE Monsoon

Monsoon Winds

SW Monsoon NE Monsoon

Position of the Low Level Jet

Features of Indian Monsoon

•Coastline borders largest land

mass on planet & near the tropics

•Himalayas focus winds & create

orographic rains

•Glacial storage of freshwater

occurs

•Persistent low level winds (Somali or Findlater Jet)

SW Monsoon

NE Monsoon

Indian Ocean Circulation

•Far more complicated than Atlantic

or Pacific

•Monsoon winds drive seasonal

changes in observed currents in

Arabian Sea

•Reversing currents include Somali,

NEC & NECC

•Somali current reaches > 3.5 m/s

•Intense open ocean upwelling

The American Monsoon

• Occurrence of July Thunderstorms

over NW Mexico & Arizona

• Driven by monsoon between

Pacific Ocean & the American

Desert

• Huge issue for flash floods

The American Monsoon

Monthly precipitation over SW U.S. & Mexico

The American Monsoon

July Convective Activity Index

The American Monsoon

The American Monsoon

• Occurrence of July Thunderstorms

over NW Mexico & Arizona

• Driven by monsoon between

Pacific Ocean & the American

Desert

• Huge issue for flash floods