The impact of local winds and long-range transport on the continuous carbon dioxide record at Mount Waliguan, China

Abstract

This paper describes the continuous measurements of atmospheric carbon dioxide at Mt. Waliguan (36°17′N, 100°54′E, 3816 m asl) in western China over the period 1994–2000. The CO2 hourly mixing ratios were segregated by horizontal wind direction/speed and vertical winds, respectively, merged by season over the entire measurement period. The short‐term variability in CO2 was examined mainly from the point of view of local winds observed at this station and isobaric back trajectory cluster‐concentration analysis as for local and long‐range transport influence, to permit the selection of hourly average data that is representative of background conditions. From the selected hourly data, daily, monthly and annual averages that are not influenced by local CO2 sources and sinks be computed by discriminating the local and regional impact on the Waliguan CO2 records. On the basis of these results, background CO2 data were then analyzed to evaluate the averaged diurnal variation, monthly mean time series, CO2 mixing ratio distribution in different seasons as well as averaged seasonal cycle. Annual mean and growth rate of CO2 at Waliguan during the period of 1991 to 2000 were further discussed by supplement with NOAA/CMDL flask air sampling records at this station and other monitoring stations located at similar latitudinal band in the Northern Hemisphere. The results from this study can provide atmospheric CO2 characteristics in Asian inland regions, and be used in other studies to improve the understanding of carbon source and sink distributions.

Long term particle size distribution measurements at Mount Waliguan, a high-altitude site in inland China

“…The monthly average temperatures vary from −10 • C in mid-winter to 10 • C in summer. The wind direction is mostly from east and north-east in summer and from west in winter (Zhou et al, 2003). The Yearly-average wind speed is 4.6 m/s.…”

Correlation slopes of GEM / CO, GEM / CO<sub>2</sub>, and GEM / CH<sub>4</sub> and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

“…Atmospheric CO 2 and CH 4 at XGL were measured using the G1301 CRDS, and CO was measured by the G1302 CRDS. Detailed information regarding the schematic of the analytical systems, air collections, calibrations, and data processing has been addressed in previous studies (Zhou et al, 2003;Fang et al, 2013). The analytical precisions for the atmospheric CO 2 , CH 4 , and CO measurements were approximately 0.07 µmol mol −1 (ppm), 1.5 nmol mol −1 (ppb), and 2.0 nmol mol −1 (ppb), respectively.…”

In-situ measurements of atmospheric hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) at the Shangdianzi regional background station, China

“…The combination of in-situ measurements with meteorological data can improve the understanding of the relationship between enhanced concentrations and emissions (Dlugokencky et al, 1993;Zhou et al, 2004). In this study, the impacts of local winds on atmospheric HFC and PFC mixing ratios were investigated based on one year of observations.…”

“…The surface wind data was calculated based on the sampling time of the in-situ measurement and was then separated into 16 wind directions. Mixing ratio anomalies (differences between mixing ratios in each wind sector and their means) and loadings (mixing ratio anomalies weighted by time (8760 h) associated with winds in a given sector) were calculated based on the method described in the previous studies Zhou et al, , 2004. Both anomalies and loadings are performed on the full set of measurements.…”