Recent content by meteo student

  1. M

    I Converting from spherical to cylindrical coordinates

    So the motivation for doing this and it is a research level question - is given all the coordinates of a vortex(or a hurricane) - is the hurricane axisymmetric or not ? As a first step in answering that is to convert to a cylindrical coordinate system where it maybe possible to answer that...
  2. M

    I Converting from spherical to cylindrical coordinates

    BvU - One hundred per cent correct.
  3. M

    I Converting from spherical to cylindrical coordinates

    one way to get through this problem and I would like some feedback on the approach I am taking right now - is to convert from a global spherical to a local spherical coordinate system and then convert the local spherical to local cylindrical.
  4. M

    I Converting from spherical to cylindrical coordinates

    Yes apologies what I meant by grid point is the surface of a sphere. And yes you are right I was wrong when I wrote that the longitude transforms unchanged. I am looking for the appropriate transformation equation from a global spherical coordinate to a local cylindrical coordinate system...
  5. M

    I Converting from spherical to cylindrical coordinates

    When you write "vortex and grid point" you mean the center of the vortex and grid point is that correct ? So that defines my radius vector in the local coordinate system. From which I can get the magnitude of the radius vector which is nothing but the local radius. Finally the longitude...
  6. M

    I Converting from spherical to cylindrical coordinates

    Again really penetrating questions( I am really learning quickly). No because the hurricane moves with time the origin of my local coordinate system is not fixed.
  7. M

    I Converting from spherical to cylindrical coordinates

    BvU - Thanks for your response. Very good question. So what I do know is that the center of the vortex(hurricane) is the center of the cylindrical coordinate system. So the radius to me is the distance from the center of the vortex to that grid point. I am talking of a coordinate system...
  8. M

    I Converting from spherical to cylindrical coordinates

    I have the coordinates of a hurricane at a particular point defined on the surface of a sphere i.e. longitude and latitude. Now I want to transform these coordinates into a axisymmetric representation cylindrical coordinate i.e. radial and azimuth angle. Is there a way to do the mathematical...
  9. M

    Fortran Handling underflow errors in fortran 90

    Tom - I agree. If you can read my response to Mark I have summarized my efforts so far. My question was how to handle an underflow error and move on. So if expr1 is a really low value such as -1.0E-45 is it reasonable to flush it to zero and move on ? That is the question I am asking here.
  10. M

    Fortran Handling underflow errors in fortran 90

    Thank you Mark for the response. I apologize for not adding the code tag. I added the tag now. Thanks also for the suggestions on the readability. Yes I already used a debugger (gdb) and could not make much progress with it.I am using gfortran and I added the breakpoint on the offending line. As...
  11. M

    Fortran Handling underflow errors in fortran 90

    I am using fortran 90 to solve a elliptic partial differential equation numerically(Poisson's equation) and I have encountered a underflow error. All the arrays involved are stored as real data types. The original expression is highlighted in the comments and the my attempt at refactoring into...
  12. M

    A Time differentiation of fluid line integrals

    I took your advice seriously and I am reading this book - An Introduction To The Geometry and Topology Of Fluid Flows by RL Ricca. I believes it introduces students of fluid mechanics to the world view of modern mathematics.
  13. M

    I Do these manifolds have a boundary?

    So the earth(and by that I mean the atmosphere and the land and the ocean) is mathematically from the viewpoint of manifolds an open surface am I correct ?
  14. M

    I Do these manifolds have a boundary?

    What if you include the atmosphere ? I mean the Earth as a sphere or an ellipsoid.
  15. M

    I Do these manifolds have a boundary?

    So in my case the earth(land + ocean + atmosphere) has no boundary am I correct ?
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