A cold wave of winter 2021 in central South America: characteristics and impacts

Abstract

During the austral winter (June–August) of 2021, the meteorological services of Brazil, Argentina, Peru, Paraguay, Bolivia, and Chile all issued forecasts for unusually cold conditions. Record-low minimum temperatures and cold spells were documented, including one strong cold wave episode that affected 5 countries. In this study, we define a cold wave as a period in which daily maximum and minimum air temperatures are below the corresponding climatological 10th percentile for three or more consecutive days. The intense cold wave event in the last week of June, 2021, resulted in record-breaking minimum daily temperatures in several places in central South America and Chile. Several locations had temperatures about 10 °C below average, central South America had freezing conditions, and southern Brazil even saw snow. The cold air surge was characterized by an intense upper-air trough located close to 35° S and 70° W. The southerly flow to the west of this trough brought very cold air northward into subtropical and tropical South America. A northward flow between the lower-level cyclonic and anticyclonic perturbations caused the intense southerly flow between the upper-level ridge and trough. This condition facilitated the inflow of near-surface cold air from southern Argentina into southeastern Brazil and tropical South America east of the Andes. In the city of São Paulo, the cold wave caused the death of 13 homeless people from hypothermia. Frost and snow across southern and southeastern Brazil caused significant damage to coffee, sugarcane, oranges, grapes, and other fruit and vegetable crops. Wine and coffee production fell, the latter by 30%, and prices of food and commodities in the region rose. Supplementary Information The online version contains supplementary material available at 10.1007/s00382-023-06701-1.

Measuring climate change’s impact on different sugarcane varieties production in the South of Goiás

“…Moreover, Fig. 2 and Tables C2 and D3 results do not confirm Marengo et al 62 . The authors demonstrate that several crop productions, including sugarcane, were impacted by the unusual cold conditions reported for the 2021 winter period (June–August).…”

“…According to Silva et al 36 results, the mean temperature is expected to present a negative relationship, while precipitation presents a positive relationship to sugarcane yield. Marengo et al 62 confirm that temperature variation impacts sugarcane yield. Concerning CO 2 emissions, according to Linnenluecke et al 26 , it is expected that this variable presents a positive impact on sugarcane yield.…”

Flood Risk Mapping during the Extreme February 2021 Flood in the Juruá River, Western Brazilian Amazonia, State of Acre

“…The highest water level that had been previously recorded was in 2017, reaching 14.24 m. The river's alert level is 11.80 m, and the overflow level is 13 m [51]. Although the flow value on the 19th was not the highest recorded, it marked the peak water level that the river had ever reached, surpassing the mark of 14.31 m, above the overflow level.…”

“…In fact, in 2021, in several municipalities in the Amazon basin, rivers reached levels higher than the maximum observed until then, making this year the biggest flood event in the entire history of monitoring [46]. The 2021 flood in Amazonia [50,51] was associated with an intensification of the atmospheric upward motion in the northern Amazonia (5 • S-5 • N) during austral summer and fall, which is related to an intensification of the Walker circulation. This atmospheric phenomenon is linked to an amplification of deep convective clouds and intense rainfall across northern Amazonia, leading to positive anomalies in terrestrial water storage during the 2021 austral summer.…”

Priming avocado with sodium hydrosulfide prior to frost conditions induces the expression of genes involved in protection and stress responses

“…Unforeseen cold spells (chilling or frost) that occur in different regions of the world, e.g. (Cramer et al, 2018), can be especially critical for non‐native trees such as avocado (Marengo et al, 2023). ‘Radiation frost’ is characterized by sub‐zero temperatures on a clear, dry night, followed by a sunny, warmer day.…”