Natural Variabilities and Trends in CO2 from the Los Angeles Megacity Measured Over 15 Years
Abstract
Urban regions are the dominant sources of greenhouse gases, comprising over 80% of global anthropogenic emissions while covering just ~3% of the land. Although urban CO2 domes result in large signals for monitoring cycles and trends, they are affected by many processes, both natural and man-made. For example, background air is affected by global patterns as observed at remote sites, and local meteorology modifies anthropogenic and biogenic sources. All of these processes must be disentangled before we can understand the trends caused by human activities. Here we show results from 15 years of flask sampling of CO2 in air from Pasadena, CA, a good receptor site for the Los Angeles basin. We use the time series of mid-afternoon data to look at the processes operating on weekly, seasonal, and inter-annual time-scales. We observe long natural oscillations such as ENSO. A distinct annual cycle is observed, but it is out of phase with the natural cycle.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.A51J..03N
- Keywords:
-
- 0345 ATMOSPHERIC COMPOSITION AND STRUCTURE Pollution: urban and regional;
- 0428 BIOGEOSCIENCES Carbon cycling;
- 0438 BIOGEOSCIENCES Diel;
- seasonal;
- and annual cycles