Influence of transport and trends in atmospheric CO2 at Lampedusa

Abstract The study of the CO2 15-year records at Lampedusa (35° 31′N, 12° 37′E) is presented in this work. Short- and long-term CO2 variability has been investigated. No significant diurnal variations are observable thus remarking the background character and representativeness of the observation site. The CO2 long-term trend shows a mean linear growth rate (GR) of 1.9 ppm yr−1. The periodic behaviour of the time series has been analysed and the mean seasonal cycle amplitude has been found to be 8.72 ppm. The seasonal cycle amplitude shows a marked interannual variability. The lowest value of the seasonal cycle amplitude has been detected in 2003, in concomitance with the strong anomalous heat wave recorded in Europe. CO2 GR behaviour has been related to global processes such as El Nino Southern Oscillation (ENSO) and global temperature (Tg). The influence of ENSO event on GR is remarkable only during 1998. CO2 GR curve shows peaks in the periods 1995, 2001 and 2005 (1.9, 3.7, 3.2 ppm yr−1 respectively) that are characterized by high Tg values and by intense biomass burning events. The anomalous decrease in the GR during the warm 2003 has been attributed to changes in the atmospheric circulation regime. Evaluation of the influence of transport on CO2 variability has been carried out using backward air-mass trajectory analysis and highlights the effect of the regional distribution of sources and sinks. The industrial activities and forests located in the Eastern European and Russian sector strongly affect the CO2 mixing ratio. The CO2 content of air-masses originating from this region is influenced in summertime by the high efficiency of the vegetation sink while in the winter period prevails the effect of industrial emissions.

[1]  P. Rayner,et al.  KEYNOTE PERSPECTIVE. The interannual variability of the global carbon cycle , 1999 .

[2]  Carl Ekdahl,et al.  Atmospheric carbon dioxide variations at Mauna Loa Observatory, Hawaii , 1976 .

[3]  R. Betts,et al.  Changes in Atmospheric Constituents and in Radiative Forcing. Chapter 2 , 2007 .

[4]  P. Rayner,et al.  The interannual variability of the global carbon cycle , 1999 .

[5]  Sander Houweling,et al.  CO 2 flux history 1982–2001 inferred from atmospheric data using a global inversion of atmospheric transport , 2003 .

[6]  P. Tans,et al.  Latitudinal distribution of the sources and sinks of atmospheric carbon dioxide derived from surface observations and an atmospheric transport model , 1989 .

[7]  F. Monteleone,et al.  Atmospheric methane in the Mediterranean: Analysis of measurements at the island of Lampedusa during 1995–2005 , 2007 .

[8]  J. Eiler,et al.  Coupling of surface temperatures and atmospheric CO2 concentrations during the Palaeozoic era , 2007, Nature.

[9]  Martin Heimann,et al.  On the influence of biomass burning on the seasonal CO2 Signal as observed at monitoring stations , 1998 .

[10]  Philippe Ciais,et al.  A burning question. Can recent growth rate anomalies in the greenhouse gases be attributed to large-scale biomass burning events? , 2005 .

[11]  R. Dargaville,et al.  The relationship between tropical CO2 fluxes and the El Niño‐Southern Oscillation , 1999 .

[12]  M. Ramonet,et al.  CO2 baseline concept in 3-D atmospheric transport models , 1996 .

[13]  Corinne Le Quéré,et al.  Climate Change 2013: The Physical Science Basis , 2013 .

[14]  P. Ciais,et al.  Europe-wide reduction in primary productivity caused by the heat and drought in 2003 , 2005, Nature.

[15]  R. Bacastow,et al.  Modulation of atmospheric carbon dioxide by the Southern Oscillation , 1976, Nature.

[16]  R. Francey,et al.  Interannual growth rate variations of atmospheric CO2 and its δ13C, H2, CH4, and CO between 1992 and 1999 linked to biomass burning , 2002 .

[17]  J. Jouzel,et al.  Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica , 1999, Nature.

[18]  P. Grigioni,et al.  Interannual variability of atmospheric CO2 in the Mediterranean: measurements at the island of Lampedusa , 2003 .

[19]  R. Feely,et al.  Influence of El Niño on the equatorial Pacific contribution to atmospheric CO2 accumulation , 1999, Nature.

[20]  J. Houghton,et al.  Climate change 2001 : the scientific basis , 2001 .

[21]  Corinne Le Quéré,et al.  Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks , 2007, Proceedings of the National Academy of Sciences.

[22]  T. J. Blasing,et al.  An estimate of monthly global emissions of anthropogenic CO2: Impact on the seasonal cycle of atmospheric CO2 , 2008 .

[23]  Ralph F. Keeling,et al.  Recording Earth's Vital Signs , 2008, Science.

[24]  A. Mariotti,et al.  Terrestrial mechanisms of interannual CO2 variability , 2005 .

[25]  Taro Takahashi,et al.  Towards robust regional estimates of CO2 sources and sinks using atmospheric transport models , 2002, Nature.

[26]  Pieter P. Tans,et al.  Evidence for interannual variability of the carbon cycle from the National Oceanic and Atmospheric Administration/Climate Monitoring and Diagnostics Laboratory Global Air Sampling Network , 1994 .

[27]  Haifeng Qian,et al.  Impact of 1998–2002 midlatitude drought and warming on terrestrial ecosystem and the global carbon cycle , 2005 .

[28]  R. Draxler.  HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) Model access via NOAA ARL READY Website , 2010 .

[29]  M. Wahlen,et al.  Interannual extremes in the rate of rise of atmospheric carbon dioxide since 1980 , 1995, Nature.

[30]  Casper Labuschagne,et al.  Saturation of the Southern Ocean CO2 Sink Due to Recent Climate Change , 2007, Science.

[31]  T. Stocker,et al.  High-resolution carbon dioxide concentration record 650,000–800,000 years before present , 2008, Nature.