<div dir="ltr">Ohhhhh @Jeff...I see what you are saying...there's an angle to the direction of the winds...you cant assume that both levels are in the same direction. That makes perfect sense. Very excellent explanation by the way. <div>
<br></div><div><br></div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Sun, Sep 1, 2013 at 10:52 PM, Jeff Duda <span dir="ltr"><<a href="mailto:jeffduda319@gmail.com" target="_blank">jeffduda319@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">I suggest you have a look through this page (<a href="http://mathworld.wolfram.com/VectorAddition.html" target="_blank">http://mathworld.wolfram.com/VectorAddition.html</a>) and the related page linked under "see also" called "vector difference". You can add/subtract two vectors by adding/subtracting the corresponding <b>components</b> (i.e., the u and v components), and making a vector of the resulting sum/difference. What you seem to be stuck on is taking the difference of the <b>magnitude</b> of the vectors rather than the difference of the components.<div>
<br></div><div>I'll use this example to help illustrate this. Suppose you had a westerly wind at 500 mb of 50 kts, and an easterly wind of 50 kts at the surface (unlikely except for possibly within a severe thunderstorm, but just bear with me). There is no difference in the wind speed between 500 mb and the sfc, but there is a difference in the direction. Clearly there is shear, but only if you look at the component form of the wind. The u- and v-components of the 500 mb wind in this example are u = 50, v = 0 (kts), whereas at the surface, the components are u = -50, v = 0 (kts). Therefore, the shear is given by (u500-usfc)<b>i</b> + (v500-vsfc)<b>j</b> = (50 - -50)<b>i</b> + (0-0)<b>j</b> = 100<b>i</b> + 0<b>j</b>. The shear vector is straight out of the west here. The magnitude is given by sqrt(ushear^2 + vshear^2), which is sqrt(100^2 + 0^2) = 100 kts of shear.</div>
<span class="HOEnZb"><font color="#888888">
<div><br></div><div>Jeff</div></font></span></div>
<br>_______________________________________________<br>
gradsusr mailing list<br>
<a href="mailto:gradsusr@gradsusr.org">gradsusr@gradsusr.org</a><br>
<a href="http://gradsusr.org/mailman/listinfo/gradsusr" target="_blank">http://gradsusr.org/mailman/listinfo/gradsusr</a><br>
<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>Nimrod Micael
</div>