subroutine ds2uv (d,s,u,v)
c
c     convert direction (d) and speed (s) to u-component and v-component
c
c     written by G. Walters - 1974 / CSU - Atmos
c
      real*4 deg2rad, a, d, s, u, v
      data deg2rad / .0174532925 /
      a = d * deg2rad
      u = - s * sin(a)
      v = - s * cos(a)
      return
      end
      subroutine uv2ds (u,v,d,s)
c
c     convert u-component and v-component to direction (d) and speed (s)
c
c     written by G. Walters - 1974 / CSU - Atmos
c
      real*4 rad2deg, u, v, d, s
      data rad2deg / 57.29577951 /
      if (v)  60, 10, 50
  10  continue
      if (u)  30, 20, 40
  20  continue
      d = 0
      s = 0
      return
  30  continue
      d = 90
      s = -u
      return
  40  continue
      d = 270
      s = u
      return
  50  continue
      d = 180. + rad2deg*atan(u/v)
      go to 70
  60  continue
      d = rad2deg*atan(u/v)
      if (u.ge.0.0)  d = d + 360
  70  continue
      s = sqrt(u*u + v*v)
      return
      end