A Ceilometer-Derived Climatology of the Convective Boundary Layer Over a Southern Hemisphere Subtropical City

Marley, Hannah G.; Dirks, Kim N.; McKendry, Ian G.; Weissert, Lena; Salmond, Jennifer

doi:10.1007/s10546-020-00579-w

Cited by 5 publications

(3 citation statements)

References 67 publications

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“…First, we considered whether seasonal changes in boundary layer height could bias our results, but only modest changes in daytime boundary layer height are observed in New Zealand cities during our sampling period from autumn (March–April–May) to winter (June–July–August). 27 Second, we evaluated the impact of meteorological variability at each site from the week-to-week variability in observed CO 2ff during the last few weeks of samples collected under Level 1 normal conditions. At most sites, the week-to-week variability in CO 2ff across all samples collected in Level 1 is no larger than the measurement uncertainty bounds ( Figure 3 and Supporting Dataset ).…”

Section: Methodsmentioning

confidence: 99%

“…Yet for this study utilizing citizen science, we were unable to collect local meteorological information at each site. First, we considered whether seasonal changes in boundary layer height could bias our results, but only modest changes in daytime boundary layer height are observed in New Zealand cities during our sampling period from autumn (March–April–May) to winter (June–July–August) . Second, we evaluated the impact of meteorological variability at each site from the week-to-week variability in observed CO 2ff during the last few weeks of samples collected under Level 1 normal conditions.…”

Section: Methodsmentioning

confidence: 99%

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Dramatic Lockdown Fossil Fuel CO₂ Decrease Detected by Citizen Science-Supported Atmospheric Radiocarbon Observations

Turnbull

Domingues

Turton

2022

Environ. Sci. Technol.

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COVID-19 lockdowns resulted in dramatic changes to fossil fuel CO 2 emissions around the world, most prominently in the transportation sector. Yet travel restrictions also hampered observational data collection, making it difficult to evaluate emission changes as they occurred. To overcome this, we used a novel citizen science campaign to detect emission changes during lockdown and engage youth in climate science. Citizen scientists collected grass samples from their garden or local park, from which we analyzed the radiocarbon content to infer the recently added atmospheric fossil fuel CO 2 mole fraction at each sampling location. The local fossil fuel CO 2 mole fractions during lockdown were compared with a “normal” nonlockdown period. Our results from 17 sites in five cities around New Zealand demonstrate dramatic reductions in traffic emissions of 75 ± 3% during the most severe lockdown restriction period. This is consistent with sparse local traffic count information and a much larger decrease in traffic emissions than reported in global aggregate estimates of emission changes. Our results demonstrate that despite nationally consistent rules on travel during lockdown, emission changes varied by location, with inner-city sites typically dominated by bus traffic showing smaller decreases in emissions than elsewhere.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Dramatic Lockdown Fossil Fuel CO₂ Decrease Detected by Citizen Science-Supported Atmospheric Radiocarbon Observations

Turnbull

Domingues

Turton

2022

Environ. Sci. Technol.

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“…However, the frequency of soundings is limited, usually in synoptic times, which is not sufficient to conduct studies of long-term trends in the height of the PBL [14,15]. Recently, some remote sensing instruments, such as ceilometers, light detection and ranging (LIDAR), and sound detection and ranging (SODAR) have become available and have been used to calculate the height of the PBL [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Nocturnal Boundary Layer Erosion Analysis in the Amazon Using Large-Eddy Simulation during GoAmazon Project 2014/5

et al. 2021

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This study investigated the erosion of the nocturnal boundary layer (NBL) over the central Amazon using a high-resolution model of large-eddy simulation (LES) named PArallel Les Model (PALM) and observational data from Green Ocean Amazon (GoAmazon) project 2014/5. This data set was collected during four intense observation periods (IOPs) in the dry and rainy seasons in the years 2014 (considered a typical year) and 2015, during which an El Niño–Southern Oscillation (ENSO) event predominated and provoked an intense dry season. The outputs from the PALM simulations represented reasonably well the NBL erosion, and the results showed that it has different characteristics between the seasons. During the rainy season, the IOPs exhibited slow surface heating and less intense convection, which resulted in a longer erosion period, typically about 3 h after sunrise (that occurs at 06:00 local time). In contrast, dry IOPs showed more intensive surface warming with stronger convection, resulting in faster NBL erosion, about 2 h after sunrise. A conceptual model was derived to investigate the complete erosion during sunrise hours when there is a very shallow mixed layer formed close to the surface and a stable layer above. The kinematic heat flux for heating this layer during the erosion period showed that for the rainy season, the energy emitted from the surface and the entrainment was not enough to fully heat the NBL layer and erode it. Approximately 30% of additional energy was used in the system, which could come from the release of energy from biomass. The dry period of 2014 showed stronger heating, but it was also not enough, requiring approximately 6% of additional energy. However, for the 2015 dry period, which was under the influence of the ENSO event, it was shown that the released surface fluxes were sufficient to fully heat the layer. The erosion time of the NBL probably influenced the development of the convective boundary layer (CBL), wherein greater vertical development was observed in the dry season IOPs (~1500 m), while the rainy season IOPs had a shallower layer (~1200 m).

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The relationship between Brown haze, atmospheric boundary layer structure, and air pollution in an urban area of complex coastal terrain

Marley

Dirks

Neverman

et al. 2021

Atmospheric Pollution Research

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A Ceilometer-Derived Climatology of the Convective Boundary Layer Over a Southern Hemisphere Subtropical City

Cited by 5 publications

References 67 publications

Dramatic Lockdown Fossil Fuel CO₂ Decrease Detected by Citizen Science-Supported Atmospheric Radiocarbon Observations

Dramatic Lockdown Fossil Fuel CO₂ Decrease Detected by Citizen Science-Supported Atmospheric Radiocarbon Observations

Nocturnal Boundary Layer Erosion Analysis in the Amazon Using Large-Eddy Simulation during GoAmazon Project 2014/5

The relationship between Brown haze, atmospheric boundary layer structure, and air pollution in an urban area of complex coastal terrain

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A Ceilometer-Derived Climatology of the Convective Boundary Layer Over a Southern Hemisphere Subtropical City

Cited by 5 publications

References 67 publications

Dramatic Lockdown Fossil Fuel CO2 Decrease Detected by Citizen Science-Supported Atmospheric Radiocarbon Observations

Dramatic Lockdown Fossil Fuel CO2 Decrease Detected by Citizen Science-Supported Atmospheric Radiocarbon Observations

Nocturnal Boundary Layer Erosion Analysis in the Amazon Using Large-Eddy Simulation during GoAmazon Project 2014/5

The relationship between Brown haze, atmospheric boundary layer structure, and air pollution in an urban area of complex coastal terrain

Contact Info

Product

Resources

About

Dramatic Lockdown Fossil Fuel CO₂ Decrease Detected by Citizen Science-Supported Atmospheric Radiocarbon Observations

Dramatic Lockdown Fossil Fuel CO₂ Decrease Detected by Citizen Science-Supported Atmospheric Radiocarbon Observations