Thank you for your interest in attending the 10th International Symposium on Tropospheric Profiling, hosted by Colorado State University.
International participants arriving from outside the United States with passports from 38 countries in the Visa Waiver Program (VWP) who have machine-readable passports may be able to travel without a visa. However, a valid Electronic System for Travel Authorization (ESTA) approval is required for all participants in VWP to travel to the United States. ESTA is a free, automated system used to determine the eligibility of visitors to travel to the United States under the VWP. Participants from other countries will need a B-1 (business) visa or B-2 (tourist) visa.
Note: Obtaining U.S. visas may require a visit to a U.S. consulate or embassy, payment of a fee, and significant wait time. Please contact the local U.S. consulate or embassy for the up to date information.
Letter of invitation
If you require an invitation letter for U.S. Visa purposes, please request one from the following web page. A letter will be created and emailed to you within 72 hours.