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MAX-DOAS measurements in Cape Fuguei
Introduction Instrument Data References Links Acknowledgments Contact
Introduction:
As part of the DFG funded IPToT project (Investigation of Pollution Transport to Taiwan), a MAX-DOAS instrument was deployed in Cape Fuguei, a research station at the northern tip of Taiwan at 25.3°N, 121.54°E. The project, which is a collaboration between University of Bremen and the Research Centre for Environmental Changes (RCEC) at the Academia Sinica aims at the investigation of transport of pollution to and from the island of Taiwan. The instrument started operations in June 2023 and performs elevation scans in two azimuthal directions: To the north and to the east.
The location of the instrument makes it a background station, with few local pollution sources. However, transport of pollution from the city of Taipei and other parts of Taiwan, emissions from closeby ships, and long-range transport for example from mainland China lead to episodes of enhanced pollution.
Instrument:
The instrument, which is owned and operated by RCEC, consists of a temperature stabilised grating spectrometer covering the spectral range of 297 – 399 nm, equipped with a cooled UV enhanced CCD detector. The spectrometer is located inside the station's building and connected to the telescope on the roof via a quartz fibre bundle. The telescope can point at nearly every position of the upper hemisphere and includes a video camera for scene documentation. During most of the year, the prevailing wind direction is from the northeast, bringing clean ocean air to the station. Only in summer winds from westerly and southerly directions dominate. More on the instrument and measurement principle can be found on our MAXDOAS page.
Data:
An overview on the first two years of measurements (July 2023 - June 2025) is given below. Shown are the differential slant column densities (DSCD) taken in the 1° elevation angle with the closest zenith measurement as reference. This geometry gives the largest sensitivity to absorbers located close to the ground. For each of the four absorbers NO2, HCHO, SO2, and HONO, the mean diurnal variation is shown, separated for the four seasons. As can be seen, both NO2 and HONO have pronounced early morning peaks, while HCHO and SO2 peak later in the morning. Summer values are higher for all species, presumably because the main wind direction in summer is from the southwest while it is from the northeast for the rest of the year. The NO2 morning peak is explained by northward transport of pollution from sources throughout the western coast of Taiwan over the ocean, which can also be seen in GEMS satellite observations.
If you have any requests, please contact André Seyler.
References:
Links:
- This instrument is operated in co-operation with the Research Centre for Environmental Changes (RCEC) at the Academia Sinica.
Acknowledgments:
This project was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) / Gefördert durch die Deutsche Forschungsgemeinschaft (DFG) - project number 448170346.
Contact:
If you are interested in more information or would like to have access to our data, please contact André Seyler.