The results of studying spatial-temporal CO2 variations near St. Petersburg in 2014-2017 based on satellite measurements (OCO-2 satellite) and ground-based spectroscopic and local measurements are presented. According to satellite data, the full amplitude of the spatial-temporal variations for the average CO2 mixing ratio (XCO2) amount to 57.7 ppm (over 14%). The maximal XCO2 spatial variations during 1 day of observations (March 17, 2015) were 46.8 ppm (more than 10%). A comparison of CO2 satellite and ground-based spectroscopic measurements has shown that ground-based measurements in the NDACC observation system after the correction of systematic differences from the TCCON system can be used to validate satellite measurements. Ground-based local measurements of the near-surface CO2 mixing ratio at Peterhof do not correlate either with spectroscopic ground-based or satellite measurements due to both mesoscale CO2 variations and significantly different spatial averaging kernels of direct and remote measurements.