## 2 Materials and Methods
### Data Analysis  
The daily means were calculated from 3 h and 1 h reanalysis datasets on temperature and precipitation, respectively. In the next step, they were used to determine the values of the air temperature and precipitation at the location of the FLUXNET station by averaging 4 adjacent grid points. It allowed for a reasonable approximation of meteorological parameters at selected flux tower locations, presented in continuous time series.  
The temperature anomalies were calculated by removing the daily mean, calculated over the period 1991-2021. For the precipitation, the daily anomalies were not calculated as in the region characterized by lack of precipitation during some periods, the daily anomalies were not informative.  
The mean daily net ecosystem CO\({}_{2}\) fluxes were calculated by averaging 30 min FLUXNET data sets. Gaps in the CO\({}_{2}\) flux measurement records were filled using standard algorithms provided by the REddyProc online tool, which was based on procedures described by [PERSON] et al. [40]. The daily anomalies of CO\({}_{2}\) fluxes were calculated as the difference between mean daily and mean monthly CO\({}_{2}\) fluxes over the available observation period at each station.  
The periods with extreme weather conditions were defined using two methods:  
* as a period when the daily mean temperature anomaly / daily precipitation amount exceeded 95% (90%) quantile (for extreme high temperature and precipitation) or did not reach 5% (10%) quantile (for extreme low temperature and precipitation) of probability density function (PDF);as a period when the daily mean temperature anomaly exceeded one standard deviation (STD) calculated for each calendar month over the whole time series;
* as the precipitation was not normally distributed, the threshold definition based on the STD exceeding was less informative. Therefore, only the quantile thresholds were applied for precipitation.  
The combined exceeding of the PDFs of daily temperature anomalies (T) and daily precipitation amount (p) was obtained for the four combinations of temperature and precipitation quantiles, i.e., T5(10)/p5(10), T5(10)/p95(90),T95(90)/p5(10), and T95(90)/p95(90), which defined, respectively, the cool/dry (CD), cool/wet (CW), hot/dry (HD), and hot/wet (HW) extreme conditions. Subscripts 5, 10, 90, and 95 referred to the respective quantile level for temperature and precipitation.  
The PDFs were calculated for every month of the observation periods and averaged over 1991-2021. The normal distribution for the temperature and the Weibull distribution for the precipitation were used that were demonstrated to be the most appropriate for the continents in the tropics [41].  
The extreme daily CO2 flux anomaly was defined as an anomaly greater (lower) than 1 STD (\(-1\) STD). The STD was calculated separately for each calendar month to exclude the influence of the seasonal cycle. The quantile thresholds were not applied to CO2 fluxes because the PDF of CO2 fluxes varied significantly between the ecosystem type that complicated the choice of the theoretical distribution to approximate the CO2 flux data. Moreover, the short time series available at several stations also made it difficult to identify the appropriate theoretical PDF.