[What is the biggest conference in Applied Mathematics?]

Also are there a lot of isolation within the department? If I study computational chemistry, for example, I will be talking to chemists, and not to those in finance, civil engineering, computer science in the same department?

[What is the biggest conference in Earth and Atmospheric Science?]

I am looking for the biggest conference in earth and atmospheric science. I am formerly a student in physics, and I have some interest to do ph.d in this field. However I fear there is not as much as math in applied mathematics or physics, or that employment opportunity is going to be very limited after graduate school. Can you give me suggestions?

[Can I be in a Ph.D program?]

I have been in physics Ph.D program for 4 years, didn't find the department supportive, and lost interest in my studies. I am very interested in going into another field, like mathematics, geophysics, environmental physics, economy, and law. I have a decent math background, but I lack experience in each. With my criterions:

undergrad GPA: 3.6

grad GPA: most graded on Satisfactory/Unsatisfactory, received all satisfactory

GRE: 1500

Letter of Recommendation: 1 letter from grad school advisor, the only grad advisor I found very supportive of me, 2 letters have to come from undergrad

One undergrad publication, no grad publication

Not a Ph.D candidate

what are my chances of switching field?

I'm very unconfident about applying to Ph.D because I'm very worried that my GPA is too low.