<div dir="ltr"><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div>Dear NCL experts,</div><div><br></div><div>I have been using the divergence (via spherical harmonics) routine in NCL:</div><div><a href="https://www.ncl.ucar.edu/Document/Functions/Built-in/uv2dvF-1.shtml">https://www.ncl.ucar.edu/Document/Functions/Built-in/uv2dvF-1.shtml</a><br></div><div><br></div><div>Based on previous literatures, the divergence can be decomposed to its directional (diffluence) and speed (stretching) components (natural coordinates).</div><div><br></div><div><a href="https://www.weather.gov/media/wrh/online_publications/TAs/ta9139.pdf">https://www.weather.gov/media/wrh/online_publications/TAs/ta9139.pdf</a><br></div><div><a href="http://www.inscc.utah.edu/~steenburgh/classes/5110/lecture_notes/divergence+deformation.pdf">http://www.inscc.utah.edu/~steenburgh/classes/5110/lecture_notes/divergence+deformation.pdf</a><br></div><div><br></div><div>[1] Is it possible to extract these terms in NCL?</div><div>[2] If yes, I would like to ask for suggestions on how to do this in NCL.</div><div><br></div><div>Sincerely,</div><div><br></div><div>Lyndz</div></div></div></div></div></div></div></div></div></div></div>