Month: June 2023

Thursday saw both unusually low carbon dioxide concentrations and a relatively flat pattern across the 24 hours. The most likely explanation is the same as for 26 Jun – stronger than normal winds (20 km/h at 9 a.m. and 26 km/h at 3 p.m. recorded at Archerfield, and both, unusually, from due west).  This would tend to bring in air from outside the urban area, and less influenced by anthropogenic sources.  Future analysis will look more closely at wind direction effects as they could throw some light on urban carbon dioxide concentrations. 

Daily Averages – Phase 2 (See explanation of differences between Phase 1 and Phase 2 data)

For reference, latest monthly average (May 2023) from CSIRO for Kennaook/Cape Grim in NW Tasmania was 415.7 ppm. (Note – these are provisional values, subject to revision folllowing sensor re-calibrations and other checks.)

Date	Petrie Terrace	Chapel Hill	Bellbird Park
29-Jun-2023	415 ppm	409 ppm	405 ppm
28-Jun-2023	435 ppm	427 ppm	428 ppm
27-Jun-2023	426 ppm	409 ppm	415 ppm
26-Jun-2023	412 ppm	402 ppm	412 ppm
25-Jun-2023	447 ppm	426 ppm	429 ppm
24-Jun-2023	427 ppm	417 ppm	423 ppm
23-Jun-2023	434 ppm	427 ppm	435 ppm
22-Jun-2023	442 ppm	425 ppm	436 ppm
21-Jun-2023	443 ppm	421 ppm	437 ppm
20-Jun-2023	421 ppm	414 ppm	417 ppm
19-Jun-2023	430 ppm	418 ppm	419 ppm
18-Jun-2023	436 ppm	426 ppm	434 ppm
17-Jun-2023	440 ppm	429 ppm	437 ppm
16-Jun-2023	438 ppm	421 ppm	433 ppm
15-Jun-2023	433 ppm	412 ppm	428 ppm
14-Jun-2023	435 ppm	425 ppm	438 ppm
13-Jun-2023	441 ppm	436 ppm	442 ppm
12-Jun-2023	442 ppm	439 ppm	448ppm
11-Jun-2023	443 ppm	441 ppm	451 ppm
10-Jun-2023	446 ppm	432 ppm	4444 ppm
9-Jun-2023	441 ppm	428 ppm	440ppm

A very different and more normal pattern today than yesterday, which began with quite low levels.  It’s noteworthy that the very low levels (average concentration at 409 ppm) on Monday (26 June) seen at all three sites coincided with strong winds from the west (26 km/h at Archerfield at both 9 a.m. and 3 p.m.).  In contrast, the highest averages across the three sites for June (in Phase 2 data) occurred on June 11 and 12 (445 and 443 ppm), two days of low or no winds.  This is consistent with higher carbon dioxide concentrations accumulating in calm weather, and being diluted when fresh winds blow across the city, especially from the west where two of the monitors are located, meaning that these winds travel over relatively less urban land.

Daily Averages – Phase 2 (See explanation of differences between Phase 1 and Phase 2 data)

For reference, latest monthly average (Apr 2023) from CSIRO for Kennaook/Cape Grim in NW Tasmania was 415.4 ppm. (Note – these are provisional values, subject to revision folllowing sensor re-calibrations and other checks.)

Date	Petrie Terrace	Chapel Hill	Bellbird Park
28-Jun-2023	435 ppm	427 ppm	428 ppm
27-Jun-2023	426 ppm	409 ppm	415 ppm
26-Jun-2023	412 ppm	402 ppm	412 ppm
25-Jun-2023	447 ppm	426 ppm	429 ppm
24-Jun-2023	427 ppm	417 ppm	423 ppm
23-Jun-2023	434 ppm	427 ppm	435 ppm
22-Jun-2023	442 ppm	425 ppm	436 ppm
21-Jun-2023	443 ppm	421 ppm	437 ppm
20-Jun-2023	421 ppm	414 ppm	417 ppm
19-Jun-2023	430 ppm	418 ppm	419 ppm
18-Jun-2023	436 ppm	426 ppm	434 ppm
17-Jun-2023	440 ppm	429 ppm	437 ppm
16-Jun-2023	438 ppm	421 ppm	433 ppm
15-Jun-2023	433 ppm	412 ppm	428 ppm
14-Jun-2023	435 ppm	425 ppm	438 ppm
13-Jun-2023	441 ppm	436 ppm	442 ppm
12-Jun-2023	442 ppm	439 ppm	448ppm
11-Jun-2023	443 ppm	441 ppm	451 ppm
10-Jun-2023	446 ppm	432 ppm	4444 ppm
9-Jun-2023	441 ppm	428 ppm	440ppm

Travels interrupted posting for the last few days, but with time to carefully check all Python analysis code, the averages for the last 19 days are presented here without resorting to Excel.  The tabulated data receives a minor revision between June 09 and June 18 (data for June 19 and subsequent dates is new today.  The checks caught an inadvertent double application of calibration coefficients – making a very small difference to some data, in no case > 2ppm). Phase 2 data (see explanation here) has accumulated to the point where the average values in Fig 2 show a fairly clear pattern.  The CBD concentrations are marginally higher than the others overall, but are notably higher in daylight hours, while the city edge data (Bellbird Park) has higher values at night, possibly because of higher night-time respiration from vegetation.  The final image is of a meeting I had with final year PhD student Naomi Askow at U.C. Berkeley – Naomi is on Prof. Ron Cohen’s ‘Beaco2n’ project team – and generously shared some of her time explaining aspects of their more established project.  On display is their sensor equipment which is the basis for their extensive Bay Area network. Many useful ideas came from this meeting.

Daily Averages – Phase 2 (See explanation of differences between Phase 1 and Phase 2 data)

For reference, latest monthly average (Apr 2023) from CSIRO for Kennaook/Cape Grim in NW Tasmania was 415.4 ppm. (Note – these are provisional values, subject to revision folllowing sensor re-calibrations and other checks.)

Date	Petrie Terrace	Chapel Hill	Bellbird Park
27-Jun-2023	426 ppm	409 ppm	415 ppm
26-Jun-2023	412 ppm	402 ppm	412 ppm
25-Jun-2023	447 ppm	426 ppm	429 ppm
24-Jun-2023	427 ppm	417 ppm	423 ppm
23-Jun-2023	434 ppm	427 ppm	435 ppm
22-Jun-2023	442 ppm	425 ppm	436 ppm
21-Jun-2023	443 ppm	421 ppm	437 ppm
20-Jun-2023	421 ppm	414 ppm	417 ppm
19-Jun-2023	430 ppm	418 ppm	419 ppm
18-Jun-2023	436 ppm	426 ppm	434 ppm
17-Jun-2023	440 ppm	429 ppm	437 ppm
16-Jun-2023	438 ppm	421 ppm	433 ppm
15-Jun-2023	433 ppm	412 ppm	428 ppm
14-Jun-2023	435 ppm	425 ppm	438 ppm
13-Jun-2023	441 ppm	436 ppm	442 ppm
12-Jun-2023	442 ppm	439 ppm	448ppm
11-Jun-2023	443 ppm	441 ppm	451 ppm
10-Jun-2023	446 ppm	432 ppm	4444 ppm
9-Jun-2023	441 ppm	428 ppm	440ppm

On Sunday there was an overal drop in concentrations at the three sites by the end of the day, the lagest drop being at the city centre site (Petrie Terrace), in this tenth day of Phase 2 data (see explanation here). Today’s third graph shows data for concentrations (black dots and open black circles) for two heights above a southern Finnish boreal forest. Faassen, Kim A. P., Linh N. T. Nguyen, Eadin R. Broekema, Bert A. M. Kers, Ivan Mammarella, Timo Vesala, Penelope A. Pickers, et al. ‘Diurnal Variability of Atmospheric O₂, CO₂, and Their Exchange Ratio above a Boreal Forest in Southern Finland’. Atmospheric Chemistry and Physics 23, no. 2 (19 January 2023): 851–76. https://doi.org/10.5194/acp-23-851-2023.

Daily Averages – Phase 2 (See explanation of differences between Phase 1 and Phase 2 data)

For reference, latest monthly average (Apr 2023) from CSIRO for Kennaook/Cape Grim in NW Tasmania was 415.4 ppm. (Note – these are provisional values, subject to revision folllowing sensor re-calibrations and other checks.)

Date	Petrie Terrace	Chapel Hill	Bellbird Park
18-Jun-2023	436 ppm	427 ppm	432 ppm
17-Jun-2023	439 ppm	431 ppm	435 ppm
16-Jun-2023	437 ppm	423 ppm	431 ppm
15-Jun-2023	432 ppm	413 ppm	426 ppm
14-Jun-2023	435 ppm	427 ppm	436 ppm
13-Jun-2023	441 ppm	438 ppm	440 ppm
12-Jun-2023	442 ppm	441 ppm	446ppm
11-Jun-2023	443 ppm	443 ppm	449 ppm
10-Jun-2023	446 ppm	434 ppm	442 ppm
9-Jun-2023	440 ppm	430 ppm	438 ppm

On Saturday no major changes in the patterns of Phase 2 data (see explanation here). Today’s third graph shows comparable averaged data for two sites in Hangzhou (HZ), an industrial and high emissions area of China, and Lin’an (LAN), a suburban area, for weekdays and weekends. Fang, Shuangxi, Rongguang Du, Bing Qi, Qianli Ma, Guizhen Zhang, Binjiang Chen, and Jiayue Li. ‘Variation of Carbon Dioxide Mole Fraction at a Typical Urban Area in the Yangtze River Delta, China’. Atmospheric Research 265 (1 January 2022): 105884. https://doi.org/10.1016/j.atmosres.2021.105884.

Daily Averages – Phase 2 (See explanation of differences between Phase 1 and Phase 2 data)

For reference, latest monthly average (Apr 2023) from CSIRO for Kennaook/Cape Grim in NW Tasmania was 415.4 ppm. (Note – these are provisional values, subject to revision folllowing sensor re-calibrations and other checks.)

Date	Petrie Terrace	Chapel Hill	Bellbird Park
17-Jun-2023	439 ppm	431 ppm	435 ppm
16-Jun-2023	437 ppm	423 ppm	431 ppm
15-Jun-2023	432 ppm	413 ppm	426 ppm
14-Jun-2023	435 ppm	427 ppm	436 ppm
13-Jun-2023	441 ppm	438 ppm	440 ppm
12-Jun-2023	442 ppm	441 ppm	446ppm
11-Jun-2023	443 ppm	443 ppm	449 ppm
10-Jun-2023	446 ppm	434 ppm	442 ppm
9-Jun-2023	440 ppm	430 ppm	438 ppm