The CO2 system in rivers of the Australian Victorian Alps: CO2 evasion in relation to system metabolism and rock weathering on multi-annual time scales

Permafrost-affected soils contain a large quantity of soil organic carbon (SOC). Two processes control the amount of carbon stored in soils. The photosynthetic activity of plants produces biomass that may accumulate in the soil, while microorganism&#8217;s respiration leads to a depletion of the soil carbon stocks through decomposition. The carbon balance defines whether a soil acts as a source or sink of carbon. In recent decades, many researchers observed and analyzed the carbon balance of permafrost soils. In most cases, the focus lays on observations of the vertical carbon flux (CO2 and CH4) to estimate the carbon balance. However, there is lack of information regarding the lateral losses of carbon via dissolved organic carbon (DOC) or dissolved inorganic carbon (DIC) in ground- or rainwater.In this study, we estimate the lateral carbon fluxes from a permafrost-affected site in north-eastern Siberia, Russia. Long-term measurements of vertical carbon fluxes have been conducted at this study site. By considering both, the vertical and the lateral carbon fluxes, we estimate the complete carbon balance for one growing season in 2014 and discuss the contribution of the lateral carbon flux to the overall carbon balance.The results show that the vertical CO2 fluxes dominate the carbon balance during the growing season from June 8th &#8211; September 8th (-19 &#177; 1.2 kg-C m-2). The lateral fluxes of DOC and DIC reached values of +0.1 &#177; 0.01 and +1.4 &#177; 0.09 kg-C m-2, respectively, whereas the vertical fluxes of CH4 had values of +0.7 &#177; 0.02 kg-C m-2 integrated over this time. By considering the lateral carbon export, the net ecosystem carbon balance of the study area was reduced by 8%. On shorter time scales of days, the relationship between lateral and vertical flux changes within the growing season. Early in the growing season, the lateral carbon flux outpaces the weak vertical CO2 uptake for a few days and converts the estimated carbon balance from a sink to a source.We conclude that lateral carbon fluxes have a larger influence on the carbon balance of our study site on time scales of days (early and late growing season) and that this influence decreases with annual time scales. Therefore, the vertical carbon flux can be seen as a good approximation for the carbon balance of this study site on annual time scales.

Download Full-text

Comment on 'Local interactions between the sea and the air at monthly and annual time scales'

Quarterly Journal of the Royal Meteorological Society ◽

10.1256/smsqj.42311 ◽

1974 ◽

Vol 100 (423) ◽

pp. 127-128

Author(s):

RL BERNSTEIN

Keyword(s):

Time Scales ◽

Local Interactions ◽

Annual Time

Download Full-text

Local interactions between the sea and the air at monthly and annual time scales

Quarterly Journal of the Royal Meteorological Society ◽

10.1002/qj.49709440118 ◽

1968 ◽

Vol 94 (401) ◽

pp. 409-411 ◽

Cited By ~ 1

Author(s):

E. B. Kraus ◽

R. E. Morrison

Keyword(s):

Time Scales ◽

Local Interactions ◽

Annual Time

Download Full-text

Quantitative Analysis of the Impact of Meteorological Factors on Reference Evapotranspiration Changes in Beijing, 1958–2017

Water ◽

10.3390/w12082263 ◽

2020 ◽

Vol 12 (8) ◽

pp. 2263 ◽

Cited By ~ 1

Author(s):

Wenhui Liu ◽

Baozhong Zhang ◽

Songjun Han

Keyword(s):

Wind Speed ◽

Relative Humidity ◽

Time Scales ◽

Reference Evapotranspiration ◽

Meteorological Factors ◽

Sensitivity Coefficient ◽

Sensitivity Factor ◽

Net Radiation ◽

Annual Time ◽

Different Time Scales

The effects of meteorological factors on reference evapotranspiration (ET0) are variable on different time scales, although research tends to focus only on certain time scales. Therefore, using the meteorological data from 1958 to 2017 of Beijing, China, ET0 values over the last 60 years were calculated using Penman–Monteith method. The variation in ET0 values was thus analyzed against four meteorological factors over different time scales. The sensitivity of ET0 to these factors was assessed using a sensitivity coefficient, while the contribution of each factor to ET0 change was quantified by combining this sensitivity coefficient with the factor’s relative change rate over multiple time scales. The results showed that the sensitivity coefficient of relative humidity over different time scales were all negative, while the sensitivity coefficients of net radiation, temperature and wind speed were mostly positive. The main sensitivity factors of ET0 on different time scales varied. On annual time scales, the main factors were relative humidity and temperature. Over annual time scales, relative humidity and net radiation alternated as the main sensitivity factor; while over interannual time scales, the most sensitive factor was relative humidity during 1958–1979 and net radiation thereafter. The contribution of these four meteorological factors to ET0 also fluctuated greatly on intra-annual time scales. On daily time scales, the contributions of temperature and wind speed at the start and end of the year were large, while net radiation and relative humidity were dominant mid-year. On monthly to seasonal time scales, the contributions of these four meteorological factors to ET0 were notable. The contribution of relative humidity was largest in spring and autumn; net radiation was dominant in summer, while temperature and wind speed were dominant in winter. This research on the temporal variability of ET0 response factors is of great significance for understanding regional climate change.

Download Full-text

Possible Link Between Arctic Sea Ice and January PM10 Concentrations in South Korea

Atmosphere ◽

10.3390/atmos10100619 ◽

2019 ◽

Vol 10 (10) ◽

pp. 619 ◽

Cited By ~ 5

Author(s):

Jeong-Hun Kim ◽

Maeng-Ki Kim ◽

Chang-Hoi Ho ◽

Rokjin J. Park ◽

Minjoong J. Kim ◽

...

Keyword(s):

High Pressure ◽

South Korea ◽

Sea Ice ◽

Time Scales ◽

Korean Peninsula ◽

Barents Sea ◽

Arctic Sea Ice ◽

The Barents Sea ◽

Arctic Sea ◽

Annual Time

In this study, we investigated the possible teleconnection between PM10 concentrations in South Korea and Arctic Sea ice concentrations at inter-annual time scales using observed PM10 data from South Korea, NCEP R2 data, and NOAA Sea Ice Concentration (SIC) data from 2001 to 2018. From the empirical orthogonal function (EOF) analysis, we found that the first mode (TC1) was a large-scale mode for PM10 in South Korea and explained about 27.4% of the total variability. Interestingly, the TC1 is more dominantly influenced by the horizontal ventilation effect than the vertical atmospheric stability effect. The pollution potential index (PPI), which is defined by the weighted average of the two ventilation effects, is highly correlated with the TC1 of PM10 at a correlation coefficient of 0.75, indicating that the PPI is a good measure for PM10 in South Korea at inter-annual time scales. Regression maps show that the decrease of SIC over the Barents Sea is significantly correlated with weakening of high pressure over the Ural mountain range region, the anomalous high pressure at 500 hPa over the Korean peninsula, and the weakening of the Siberian High and Aleutian low. Moreover, these patterns are similar to the correlation pattern with the PPI, suggesting that the variability of SIC over the Barents Sea may play an important role in modulating the variability of PM10 in South Korea through teleconnection from the Barents Sea to the Korean peninsula via Eurasia.

Download Full-text