Eddy covariance (EC) measurements of carbon dioxide (CO2) in urban environments are carried out widely since the late nineties. However, long-term time series are still rare and little is known about long-term tendencies, even though cities are major sources of CO2 globally. Here a full decade of EC measurements from Basel, Switzerland, is presented. An approach for the calculation of horizontal averages is presented. It improves the significance and comparability of measured fluxes from heterogeneous environments and emphasizes the need of adequate weighting by horizontal averaging in such heterogeneous urban environments, especially for the derivation of cumulative quantities like the annual net ecosystem exchange. The urban CO2 mole fraction (ρC) is compared with regional background measurements, and good agreement in terms of long-term trend and seasonal variability is found. Over the last decade an increase of 2 ppm y1 is observed, both locally and globally. CO2 flux (FC) data are analyzed for diurnal and seasonal cycles as well as interannual variabilities. FC shows a large interannual variability in times of high source activity (e.g., during the day and in winter). In contrast, a relatively constant background flux of 5 μmolm2 s1 is found during periods of low source activity. The long-term trend of FC is mostly superimposed by the large temporal variability and is found to be 5% over the last 10 years.
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2xxUtGl
via IFTTT
Εγγραφή σε:
Σχόλια ανάρτησης (Atom)
Δημοφιλείς αναρτήσεις
-
Abstract Bromodomain proteins function as epigenetic readers that recognize acetylated histone tails to facilitate the transcription of t...
-
Objectives To optimise medical students’ early clerkship is a complex task since it is conducted in a context primarily organised to take ca...
-
Abstract Purpose Overcoming the flaws of current data management conditions in head and neck oncology could enable integrated informatio...
-
C. Julian Chen'Correspondence information about the author C. Julian ChenEmail the author C. Julian Chen, Donald A. Miller DOI: https://...
-
1 abqls-210rm.html Read the latest Journal of Clinical Neurophysiology - Vol. 37, No. 1, January 2020.eml 2 agx3v-nxz96.html Read the late...
-
Ambergris Caye's best News Source. A weekly tourism and community oriented newspaper providing local news, stories, and reports on what...
-
by Yanwei Li, Haifeng Liu, Wei Zeng, Jing Wei An increase in the osmolarity of tears induced by excessive evaporation of the aqueous tear p...
-
http://ift.tt/2p41efZ
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου