Observations Review 200 Zonal winds 400 (U,纬向风) 600 800 Midlatitude Jet -25 Annual 100 or S.P. 60S 40S 20S E.Q. 20N 40N 60N N.P. Polar-front Jet Subtropical or 一J66 Eddy-driven Jet 200 (edy) 400 Surface westerly is 600 Eddy-driven Eddy-drivem always centered and Jet 800 Jet strongest at 50 degree south and north,which 100 S.P 60S 40S 20S E.Q. 20N 40N 60N N.P. is always considered Subtropical Jet as the center of the 200 eddy-driven jet.It is 400 also the centric Eddy-driven latitude of Ferrel cell. 600 Eddy-driven et 800 JJA 60S 40S 20S E.Q. 20N 40N 60N N.P.Observations -Zonal mean fields 授课教师：张洋 7 n Zonal winds (U, 纬向⻛) S.P. 60S 40S 20S E.Q. 20N 40N 60N N.P. 200 400 600 800 1000 5 5 5 5 5 5 5 10 10 10 10 10 10 15 15 15 15 15 20 20 20 25 25 25 0 0 0 0 0 0 −5 −5 −5 −2.5 −2.5 −2.5 −2.5 Pressure (hpa) S.P. 60S 40S 20S E.Q. 20N 40N 60N N.P. 200 400 600 800 1000 5 5 5 5 5 5 5 10 10 10 10 10 10 15 15 15 15 15 20 20 20 20 20 25 25 30 25 35 40 0 0 0 0 0 0 0 −5 −5 −5 −2.5 −2.5 −2.5 − Pressure (hpa) 2.5 S.P. 60S 40S 20S E.Q. 20N 40N 60N N.P. 200 400 600 800 1000 5 5 5 5 5 5 10 10 10 10 10 15 15 15 20 20 20 25 25 30 30 35 35 40 0 0 0 0 0 0 0 − −10 10 −5 −5 −5 −5 −2.5 −2.5 −2.5 −2.5 Pressure (hpa) Annual DJF JJA Subtropical Jet Subtropical Jet Eddy-driven Jet Eddy-driven Jet Eddy-driven Jet Eddy-driven Jet Midlatitude Jet or Polar-front Jet or Eddy-driven Jet Surface westerly is always centered and strongest at 50 degree south and north, which is always considered as the center of the eddy-driven jet. It is also the centric latitude of Ferrel cell. Review