Ardupilot Wind settings problem

I am using Ardupilot with Plane and analyzing the log files. When I set the wind to 10m/s and from 180 degrees(south) I am getting some unwanted behaviour in WIND, I plot the WIND and can see something is not working properly.

But before that a question

When I use SITL with ardupilot and load a mission how the WIND is determined? it uses the PLANE code from the Ardupilot and then uses the sensor data(From where?) I don’t have a sensor, Then it estimates parameters using EKF? is it?

Another scenario is Using JSBsim simulator to estimate the wind. what is the key diffrence between these to in case of determining the wind?

I am adding my graphs of both With and without JSBsim to estimate the WIND.The first graph is with JSBsim which plots wind correctly while the second one does not. In the second plot also the east wind is included, please ignore that,the blue line is of north wind. JSBSIM error