In 2019, the southern region of Eastern Siberia (located between 45° N and 60° N) experienced heavy floods, while the northern region (between 60° N and 75° N) saw intense forest fires that lasted for almost the entire summer, from 25 June to 12 August. To investigate the causes of these natural disasters, we analyzed the large-scale features of atmospheric circulation, specifically the Rossby wave breaking and atmospheric blocking events. In the summer of 2019, two types of Rossby wave breaking were observed: a cyclonic type, with a wave breaking over Siberia from the east (110° E–115° E), and an anticyclonic type, with a wave breaking over Siberia from the west (75° E–90° E). The sequence of the Rossby wave breaking and extreme weather events in summer, 2019 are as follows: 24–26 June (cyclonic type, extreme precipitation, flood), 28–29 June and 1–2 July (anticyclonic type, forest fires), 14–17 July (both types of breaking, forest fires), 25–28 July (cyclonic type, extreme precipitation, flood), 2 and 7 August (anticyclonic type, forest fires). Rossby wave breaking occurred three times, resulting in the formation and maintenance of atmospheric blocking over Eastern Siberia: 26 June–3 July, 12–21 July and 4–10 August. In general, the scenario of the summer events was as follows: cyclonic Rossby wave breaking over the southern part of Eastern Siberia (45° N–60° N) caused extreme precipitation (floods) and led to low gradients of potential vorticity and potential temperature in the west and east of Lake Baikal. The increased wave activity flux from the Europe–North Atlantic sector caused the anticyclonic-type Rossby wave breaking to occur west of the area of a low potential vorticity gradient and north of 60° N. This, in turn, contributed to the maintenance of blocking anticyclones in the north of Eastern Siberia, which led to the intensification and expansion of the area of forest fires. These events were preceded by an increase in the amplitude of the quasi-stationary wave structure over the North Atlantic and Europe during the first half of June.

Variational approach and sensitivity theory methods are used to construct algorithms for solving the problems of environmental forecast and design. When studying the behavior of the model in the...

Air quality monitoring systems differ in composition and accuracy of observations and their temporal and spatial coverage. A monitoring system’s performance can be assessed by evaluating the accuracy of the emission sources identified by its data. In the considered inverse modeling approach, a source identification problem is transformed to a quasi-linear operator equation with the sensitivity operator. The sensitivity operator is composed of the sensitivity functions evaluated on the adjoint ensemble members. The members correspond to the measurement data element aggregates. Such ensemble construction allows working in a unified way with heterogeneous measurement data in a single-operator equation. The quasi-linear structure of the resulting operator equation allows both solving and predicting solutions of the inverse problem. Numerical experiments for the Baikal region scenario were carried out to compare different types of inverse problem solution accuracy estimates. In the considered scenario, the projection to the orthogonal complement of the sensitivity operator’s kernel allowed predicting the source identification results with the best accuracy compared to the other estimate types. Our contribution is the development and testing of a sensitivity-operator-based set of tools for analyzing heterogeneous air quality monitoring systems. We propose them for assessing and optimizing observational systems and experiments.

The socioeconomic impacts caused by floods in the south of Eastern Siberia (SES), and the expected increase in precipitation extremes over northern Eurasia, have revealed the need to search for atmospheric circulation patterns that cause extreme precipitation events (EPE) in SES, as well as their changes. We investigate the circulation patterns causing extreme precipitation in SES and Mongolia, by examining the instability and moisture transport associated with potential vorticity (PV) dynamics during two time periods: 1982–1998 and 1999–2019. The EPE were characterized by an increase in instability within the precipitation area, which was compensated by stability around the area, with the East Asian summer monsoon transport being enhanced. PV in the subtropical regions and mid-latitudes has shown the amplification of positive and negative PV anomalies to the southeast and northwest of Lake Baikal, respectively. The PV contours for EPE have shapes of cyclonic wave breaking and cutoff low. EPE accompanied by wave breaking are characterized by strong redistribution areas, with extremely high and low stability and moisture. This can lead to the coexistence of floods and droughts, and in part was the driver of the earlier revealed “seesaw” precipitation mode over Mongolia and SES. We suggest a shift of extreme precipitation to the northwest has occurred, which was probably caused by the wave propagation change.

Climatology and variability of anticyclonic (AC-type) and cyclonic (C-type) wave breaking in the region of the subtropical jet stream are investigated usin

Many large-scale dynamic phenomena in the Earth’s atmosphere are associated with the processes of propagation and breaking of Rossby waves.