{"id":786,"date":"2020-02-06T18:16:26","date_gmt":"2020-02-06T22:16:26","guid":{"rendered":"https:\/\/www2.whoi.edu\/site\/aomip\/?page_id=786"},"modified":"2021-06-18T09:27:21","modified_gmt":"2021-06-18T13:27:21","slug":"vector-rotation-fortran-code","status":"publish","type":"page","link":"https:\/\/www2.whoi.edu\/site\/aomip\/models\/vector-rotation-fortran-code\/","title":{"rendered":"Vector Rotation – Fortran Code"},"content":{"rendered":"\n\n\t

Vector Rotation – Fortran Code<\/h1>\nSUBROUTINE C_FIELD_GEO_TO_MODEL (FIELD_X,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 FIELD_Y)\n!———————————————————————–
\n! purpose: rotate a 2-d vector field from geographic to model coordinates
\n!\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 accounting for fact that vectors change orientation
\n!———————————————————————–
\n!
\n! algorithm : project geographic long\/lat components onto
\n!\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 geographic cartesian x\/y\/z components, then
\n!\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 perform euler angle rotation about three axes obtaining
\n!\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 model cartesian x”’\/y”’\/z”’ components, then
\n!\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 project model cartesian componets onto
\n!\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 model long\/lat componets (sorry!)
\n!
\n! input :
\n!
\n! FIELD_X : x field on model grid but with geographic directions
\n! FIELD_Y : y field on model grid but with geographic directions
\n!
\n! output :
\n!
\n! FIELD_X : x field on model grid but with model directions
\n! FIELD_Y : y field on model grid but with model directions
\n!
\n!———————————————————————–\n!passed arguments
\nREAL (TYPE_REAL_8),
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 INTENT (INOUT) ::
\n&
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 FIELD_X (C_NXL:C_NXH, C_NYL:C_NYH),
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 FIELD_Y (C_NXL:C_NXH, C_NYL:C_NYH)\n!local vars
\nREAL (TYPE_REAL_8) ::
\n&
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 LON_GEO,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 LAT_GEO,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 LON_MOD,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 LAT_MOD,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 X_GEO,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 Y_GEO,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 Z_GEO,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 X_MOD,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 Y_MOD,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0 Z_MOD\n

!———————————————————————–<\/p>\n!perform at one horizontal grid point at a time
\nDO J = C_NYL, C_NYH
\nDO I = C_NXL, C_NXH\n!the present vector position in model lat\/long coords.
\nLON_MOD = C_X (I)
\nLAT_MOD = C_Y (J)\n!the present vector position in geogr. lat\/long coords.
\nCALL C_MODEL_TO_GEO (LON_MOD,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 LAT_MOD,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 LON_GEO,
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 LAT_GEO)\n!convert geogr. long\/lat into geogr. cartesian
\nX_GEO =-FIELD_X (I,J) * C_SIND (LON_GEO) –
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 FIELD_Y (I,J) * C_COSD (LON_GEO) * C_SIND (LAT_GEO)
\nY_GEO = FIELD_X (I,J) * C_COSD (LON_GEO) –
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 FIELD_Y (I,J) * C_SIND (LON_GEO) * C_SIND (LAT_GEO)
\nZ_GEO = FIELD_Y (I,J) * C_COSD (LAT_GEO)\n!rotate geogr. cartesian into model cartesian
\nX_MOD = C_REVERSE (1,1) * X_GEO
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 + C_REVERSE (1,2) * Y_GEO
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 + C_REVERSE (1,3) * Z_GEO
\nY_MOD = C_REVERSE (2,1) * X_GEO
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 + C_REVERSE (2,2) * Y_GEO
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 + C_REVERSE (2,3) * Z_GEO
\nZ_MOD = C_REVERSE (3,1) * X_GEO
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 + C_REVERSE (3,2) * Y_GEO
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 + C_REVERSE (3,3) * Z_GEO\n!convert model cartesian into model long\/lat
\nFIELD_X (I,J) =-X_MOD * C_SIND (LON_MOD)
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 + Y_MOD * C_COSD (LON_MOD)\nFIELD_Y (I,J) =-X_MOD * C_COSD (LON_MOD) * C_SIND (LAT_MOD)
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 – Y_MOD * C_SIND (LON_MOD) * C_SIND (LAT_MOD)
\n&\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 + Z_MOD * C_COSD (LAT_MOD)\nENDDO
\nENDDO\n

!———————————————————————–<\/p>\n

END SUBROUTINE C_FIELD_GEO_TO_MODEL<\/p>\n\n","protected":false},"excerpt":{"rendered":"

Vector Rotation – Fortran Code SUBROUTINE C_FIELD_GEO_TO_MODEL (FIELD_X, &\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 FIELD_Y) !———————————————————————– ! purpose: rotate a 2-d vector field from geographic to model coordinates !\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 accounting for fact that vectors change orientation !———————————————————————– ! ! algorithm : project geographic long\/lat components onto !\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 geographic cartesian x\/y\/z components, then !\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 perform euler angle rotation about three axes…<\/p>\n","protected":false},"author":83,"featured_media":0,"parent":628,"menu_order":5,"comment_status":"closed","ping_status":"closed","template":"tpl-sidebar.php","meta":{"advanced-sidebar-menu\/link-title":"","advanced-sidebar-menu\/exclude-page":false},"_links":{"self":[{"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/pages\/786"}],"collection":[{"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/users\/83"}],"replies":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/comments?post=786"}],"version-history":[{"count":3,"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/pages\/786\/revisions"}],"predecessor-version":[{"id":1688,"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/pages\/786\/revisions\/1688"}],"up":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/pages\/628"}],"wp:attachment":[{"href":"https:\/\/www2.whoi.edu\/site\/aomip\/wp-json\/wp\/v2\/media?parent=786"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}