## 3 Results and Discussion  
Temporal Variability of Daily Temperature, Precipitation, and CO2 Fluxes in Various Tropical Terrestrial Ecosystems  
Analysis of the variability of daily CO2 fluxes, air temperature, and precipitation, as well as daily CO2 flux feedbacks to the anomalous temperature and precipitation events in the tropical ecosystems, showed significant variability depending on geographical locations, landscape and climate conditions, and plant species composition. Firstly, we focused on the temporal variability of the weather conditions (temperature and precipitation) and associated CO2 flux anomalies. The daily flux data from 17 measurement stations in the tropics for the entire period of measurements were analyzed (see the examples for four selected biomes in the Supplementary Materials). As an example, Figure 2 shows the temporal variability of daily temperature, precipitation, and CO2 flux anomalies for the measurement station located in the Australian savannas (Dry River, AU-Dry). The time-series analysis evidenced that the CO2 flux anomalies in the savanna and woody savanna areas usually occurred during the wet season. Positive daily CO2 flux anomalies (up to 4 gC m\({}^{-2}\) d\({}^{-1}\)) were usually observed on days with extreme precipitation (Figure 2, Figure S4a of Supplementary Materials) and were associated with high soil moisture, resulting in higher soil respiration rates [42]. This effect may have been associated with the \"Birch effect\" [43], manifested by a strong CO2 release following the rewetting of dry soils. Several phenomena connected with the effect were previously found: more nitrogen and carbon are released from soils under wetting and drying cycles than from continuously wet soils; the longer the drying period the greater the degree of decomposition and mineralization during subsequent wetting; enhanced decomposition and the mineralization of soil organic matter decline with time after rewetting [44; 45]. A sharp increase in CO2 uptake by these ecosystems, leading to negative flux anomalies, was observed between a few days and one week after heavy rains (for example the period March-April 2012 at Figure 2). It may have been due to the intensification of photosynthesis in living plants [32]. Similar effects of precipitation on CO2 uptake were previously detected at several experimental sites in savanna in Australia [46; 47] and Africa [48]. The influence of temperature on CO\({}_{2}\) fluxes in savannas is stronger in a dry season: low temperatures are accompanied by negative CO\({}_{2}\) flux anomalies (Figure S4b), mainly due to the reduction in soil and plant CO\({}_{2}\) respiration rates, whereas positive flux anomalies (increased CO\({}_{2}\) emission) tend to occur during hot periods (Figure S4c). However, all these anomalies were significantly lower than CO\({}_{2}\) flux anomalies during extreme precipitation periods. The tropical seasonal or dry forests were characterized by well manifested seasonal variability in CO\({}_{2}\) fluxes caused by plant phenology, air temperature, and precipitation. Significant negative daily CO\({}_{2}\) flux anomalies (increase in CO\({}_{2}\) uptake up to 4.0 gC m\({}^{-2}\) day\({}^{-1}\)) may have been due to photosynthesis intensification after the heavy rainfalls at the onset of the summer monsoon season (Figure S5a). Another reason for such an effect was the inhibition of soil respiration by strong rainfalls [49]. Similar but weaker (\(<\)\(-\)2.0 gC m\({}^{-2}\) day\({}^{-1}\)) negative CO\({}_{2}\) flux anomalies were also associated with negative temperature anomalies  
Figure 2: The time series of daily net CO\({}_{2}\) flux (NEE) anomaly and daily temperature anomalies (**a–c**), daily precipitation amount (**d,e**) at flux monitoring station AU-Dry (Dry River) for the period January–July 2012. The days when the daily CO\({}_{2}\) flux anomalies were greater (lower) than 1 STD of CO\({}_{2}\) time series for this station are marked by red (blue) dots.