Systems and methods for characterizing atmospheric emissions

A method for characterizing gas emissions, comprising:

• transmitting, with a first spectrometer, a first optical beam along a first path;
• retroreflecting the first optical beam into a first retroreflected optical beam that propagates back toward the first spectrometer;
• measuring the first retroreflected optical beam with the first spectrometer to generate a first absorption signal;
• transmitting, with a second spectrometer, a second optical beam along a second path;
• retroreflecting the second optical beam into a second retroreflected optical beam that propagates back toward the second spectrometer;
• measuring the second retroreflected optical beam with the second spectrometer to generate a second absorption signal;
• transmitting, with a third spectrometer, a third optical beam along a third path;
• retroreflecting the third optical beam into a third retroreflected optical beam that propagates back toward the third spectrometer;
• measuring the third retroreflected optical beam with the third spectrometer to generate a third absorption signal;
• transmitting, with a fourth spectrometer, a fourth optical beam along a fourth path;
• retroreflecting the fourth optical beam into a fourth retroreflected optical beam that propagates back toward the fourth spectrometer;
• measuring the fourth retroreflected optical beam with the fourth spectrometer to generate a fourth absorption signal;
• and
• determining one or more emission characteristics of at least one gas species within an area that is at least partially bounded by the first path, the second path, the third path, and the fourth path.