Estimation of dependence of seasonal predictability of meteorological quantities in different regions of the Northern Hemisphere on the El Niño-Southern Oscillation phenomenon

Potential predictability and rms errors of ensemble forecasting of seasonal variability of the meteorological fields are estimated for different El Niño-Southern Oscillation (ENSO) episodes in the winter and summer of 1983–2002. By means of composite analysis, the rms errors and the potential predictability index are compared for different ENSO episodes in seven regions of the Northern Hemisphere midlatitudes. It is shown that the ENSO signals have a model-resolved response in the atmospheric circulation patterns in certain extratropical regions for some meteorological quantities. Geographic distribution of the potential predictability index shows that the maximum values occur near the centers of action of the main teleconnection systems.     

Would different methodologies for assessing carbon leakage exposure lead to different risk levels? A case study of the Brazilian industry

Energy-intensive industries play an important role in low-carbon development, being particularly exposed to climate policies. Concern over possible carbon leakage in this sector poses a major challenge for designing effective carbon pricing instruments (CPI). Different methodologies for assessing carbon leakage exposure are currently used by different jurisdictions, each of them based on different approaches and indicators. This paper aims to analyse the extent to which the use of different methodologies leads to different results in terms of exposure to the risk of carbon leakage, using the Brazilian industry sector as a case study. Results indicate that carbon leakage exposure is an expected outcome of eventual CPI implementation in Brazilian industry. However, results vary according to the chosen methodology, so the definition of the criteria is paramount for assessing sectoral exposure to the risk of carbon leakage.

Key policy insights

• Despite increasing discussion about the implementation of carbon pricing on the Brazilian industrial sector, the evaluation of carbon leakage risks is still neglected.

• Assessments of the risk of carbon leakage are directly related to the indicators and criteria used by each methodology. Thus, a given subsector may present different levels of exposure to carbon leakage depending on the methodological choice.

• More than a purely technical discussion, the methodological definition of carbon leakage risk is a political discussion – it can be well-conducted, leading to the success of a CPI, or even sabotaged, by implicitly subsidizing energy-intensive industries.

     

Influence of traffic emissions on the composition of atmospheric particles of different sizes—Part 2: SEM–EDS characterization

In urban areas traffic is the major contributor to atmospheric particulate matter and exposure to these particles currently represents a serious risk to human health. The attention has been recently focused more on the particles of smaller sizes (PM_2.5) which penetrate deeper in respiratory system causing severe health effects. Therefore, more information on PM_2.5 should be provided, namely concerning morphological and chemical characterization. Aiming further evaluation of the impact of traffic emissions on public health, this work evaluated the influence of traffic on the chemical and morphological characteristics of PM₁₀ and PM_2.5, collected at one site influenced by traffic emissions and at one reference site. Chemical and morphological characteristics of 1,000 individual particles were determined by scanning electron microscopy combined with energy dispersive spectrometer (SEM–EDS). Cluster analysis (CA) was used to identify different types of particles that occurred in PM, aiming the identification of the respective emission sources. Traffic PM_2.5 were dominated by particles composed of Fe oxides and alloys (67%) which were related to traffic emissions (this percentage was 3.7 times higher than at the background site); in PM_2.5–10 the abundance of Fe oxides and alloys were 20% and 0% for the traffic and background sites, respectively. Background PM_2.5 were mainly constituted by aluminum silicates (63%) related to natural sources (this percentage was 2.5 times higher than at the traffic site); the abundances of aluminum silicates in PM_2.5–10 were 74% and 73% for traffic and background sites, respectively. It was concluded that traffic emissions were mainly present in PM_2.5 (the percentage of particles associated to these emissions was 3.4 times higher than in PM_2.5–10), while coarse particles were dominated by material of natural origin (the percentage of particles associated was 1.2 and 3.0 times higher than in PM_2.5 for traffic and background sites, respectively). Previous results obtained by proton induced X-ray emission (PIXE) were consistent with SEM–EDS analysis that showed to be very useful to complement elemental analysis of different PM_2.5 and PM_2.5–10.     

Impact of land–sea breezes at different scales on the diurnal rainfall in Taiwan

The formation mechanism of diurnal rainfall in Taiwan is commonly recognized as a result of local forcings involving solar thermal heating and island-scale land–sea breeze (LSB) interacting with orography. This study found that the diurnal variation of the large-scale circulation over the East Asia-Western North Pacific (EAWNP) modulates considerably the diurnal rainfall in Taiwan. It is shown that the interaction between the two LSB systems—the island-scale LSB and the large-scale LSB over EAWNP—facilitates the formation of the early morning rainfall in western Taiwan, afternoon rainfall in central Taiwan, and nighttime rainfall in eastern Taiwan. Moreover, the post-1998 strengthening of a shallow, low-level southerly wind belt along the coast of Southeast China appears to intensify the diurnal rainfall activity in Taiwan. These findings reveal the role of the large-scale LSB and its long-term variation in the modulation of local diurnal rainfall.     

The impact of El Ni?o on South American summer climate during different phases of the Pacific Decadal Oscillation

In austral summer, the observed El Ni?o (EN) events during warm Pacific Decadal Oscillation (PDO) phases (PDO(+)) exhibited large anomalous upper level wave patterns in response to larger Sea Surface Temperature (SST) anomalies in the Equatorial Pacific and Atlantic Oceans compared with SST anomalies in EN events during cold PDO phases (PDO(?)). The precipitation anomalies in PDO(+) EN are increased over Southeastern South America (SESA) associated with the intensification of the moisture flux convergence in this region. The PDO(?) EN events exhibit positive precipitation anomalies only over southern SESA, while negative anomalies were observed in the north. Downward motion and anomalous divergence over central eastern Brazil may have contributed to the weakening of the northwesterly moisture flux convergence associated with the South American Low Level Jet (SALLJ) over the subtropics. The extratropical cyclones showed higher frequency and lower central pressures in southern Brazil, Uruguay, northeastern Argentina, and Southwest Atlantic Ocean during the PDO(+) EN events compared with the PDO(?) EN events. Such increase in the frequency and intensity of cyclogenesis cases seems to be in accordance with the anomalous moisture flux convergence over the SESA and associated reduction in the Sea Level Pressure observed during PDO(+) EN events. In order to investigate the impact of a canonical El Ni?o event over South America under different PDO phases, two numerical experiments were done with an Atmospheric General Circulation Model. Global SST and ice sea fields average over years characterized by (a) PDO(+) and (b) PDO(?) were considered as climatologically fields, and a composite of anomalies of SST of all El Ni?o events observed in 1950?C1999 was added in the region 20oS?C20oN;120oW?C175oW of both ??climatologies.?? The differences in experiments suggest that a canonical EN may produce significant different anomalous atmospheric patterns associated with distinct PDO climatologies. The more significant differences are simulated over extreme northern and eastern Brazil. Additional numerical experiments isolating the observed variability of SST over several oceanic basins during different PDO phases will be conducted to study their particular role on the South American climate.     

Precipitation–altitude relationships on different timescales and at different precipitation magnitudes in the Qilian Mountains

It is generally accepted that altitude is the main variable governing the spatial distribution of precipitation in the mountains. This study mainly discusses the precipitation–altitude relationships on different timescales and at different individual precipitation magnitudes in the entire study period (April 2012 to September 2015), wet season (May to September), and dry season (October to April), and tries to find a threshold to determine whether the correlation between precipitation and altitude is significant. In this study, the half-hourly data, including precipitation, wind speed, and air temperature, from April 2012 to September 2015 are obtained by six automatic meteorological stations located on the north slope of Qilian Mountains, which range from 2980 to 4484 m a.s.l., and horizontal distance is approximately 7000 m. Results indicate that (i) if all samples in the entire study period are to be investigated, the individual precipitation had to reach about 30 or 40 mm, then the sample may pass the significance test at p < 0.05 or at p < 0.01, respectively. The thresholds in wet season are same as that during entire study period. The thresholds in dry season are about 10 and 15 mm (ii) with increasing timescale, the percentage of samples that pass the test increases. However, it is until the monthly scale whether it is wet or dry season or the entire study period, the precipitation–altitude relationships have statistical significance and using the monthly or yearly scale as the time unit can be better applied to the research, which is based on the precipitation–altitude relationships.     

Simulation of two types of El Niño from different convective parameters

Many recent studies have reported the presence of two types of El Niño events in observation: Cold Tongue (CT) El Niño and Warm Pool (WP) El Niño. We investigate the sensitivity of a model simulating two types of El Niño by changing a convective triggering parameter (Tokioka parameter). When deep convections are highly suppressed with a large Tokioka parameter, the model is capable of simulating distinct two-types of El Niño. However, the model has a problem in simulating two-types of El Niño distinctively when the Tokioka parameter is small, because the location of the maximum precipitation anomaly related to the CT El Niño is significantly shifted westward, leading to an atmospheric response pattern similar to that of the WP El Niño. Our results suggest that the mean precipitation over the eastern equatorial Pacific and the resultant zonal distribution in atmospheric feedback associated with ENSO can be one of the crucial factors for simulating two-types of El Niño.     

Analysis of Basic Features of the Onset of the Asian Summer Monsoon

In this paper,a relatively systematic climatological research on the onset of the Asian tropical summer monsoon(ATSM)was carried out.Based on a unified index of the ATSM onset,the advance of the whole ATSM was newly made and then the view that the ATSM firstly breaks out over the tropical eastern Indian Ocean and the middle and southern Indo-China Peninsula was further documented,which was in the 26th pentad(about May 10),then over the South China Sea(SCS)in the 28th pentad.It seems that the ATSM onset over the two regions belongs to the different stages of the same monsoon system.Then,the onset mechanism of ATSM was further investigated by the comprehensive analysis on the land-sea thermodynamic contrast,intraseasonal oscillation,and so on,and the several key factors which influence the ATSM onset were put forward.Based on these results,a possible climatological schematic map that the ATSM firstly breaks out over the tropical eastern Indian Ocean,the Indo-China Peninsula,and the SCS was also presented, namely seasonal evolution of the atmospheric circulation was the background of the monsoon onset;the enhancement and northward advance of the convections,the sensible heating and latent heating over the Indo-China Peninsula and its neighboring areas,the dramatic deepening of the India-Burma trough,and the westerly warm advection over the eastern Tibetan Plateau were the major driving forces of the summer monsoon onset,which made the meridional gradient of the temperature firstly reverse over this region and ascending motion develop.Then the tropical monsoon and precipitation rapidly developed and enhanced. The phase-lock of the 30-60-day and 10-20-day low frequency oscillations originated from different sources was another triggering factor for the summer monsoon onset.It was just the common effect of these factors that induced the ATSM earliest onset over this region.     

Influences of the Extratropical Pacific SST on the Precipitation of the North China Region

ＩｎｆｌｕｅｎｃｅｓｏｆｔｈｅＥｘｔｒａｔｒｏｐｉｃａｌＰａｃｉｆｉｃＳＳＴｏｎｔｈｅＰｒｅｃｉｐｉｔａｔｉｏｎｏｆｔｈｅＮｏｒｔｈＣｈｉｎａＲｅｇｉｏｎＧｅｎｇＱｕａｎｚｈｅｎ（耿全震），ＤｉｎｇＹｉｈｕｉ（丁一汇）ａｎｄＨｕａｎｇＣｈａｏｙｉｎｇ...     

The Dynamic Mechanism of the Formation of the Low Level Jet

The ordinary multidimensional reductive perturbation method is generalized so as to apply to the general case including the dissipative factor. With this the corresponding Cubic-Schrbdinger equation is deduced, and by the preliminary study of its solution, it shows that it is more admissible to consider atmospheric meso-scale systems as the nonlinear Cubic-Schrbdinger waves.With suitable boundary and initial conditions, the Cubic-Schrodinger equation is numerically integrated so as to investigate the possible dynamic mechanism as well as the impacts of the nonlinear action, turbulent friction and topogrphy to the formation of the LLJ. The results indicate that the downward transfer of the momentum and the effect of the surface friction are responsible for the concentration of the momentum in the layer between 850 and 700 hPa. The location of the horizontal concentration of momentum depends on the propagation of momentum, in the process the inertia-gravity internal wave is very important, whereas turbule     

The Theory Study of the Influence of the Topography on the Cold Frontal Motion

In order to study the characteristics of cold frontal motion over the arbitrary topography, the velocity of cold frontal movement is derived by using the one layer shallow-water model. The results show that there exist the retardation in upwind side and rapid descent in the lee slope when the cold front crosses the topography.     

The distribution of the total ozone values in the end of the polar winter—the key to the forecast of extreme seasons?

The possibility to use the observations of the total ozone values in the atmosphere (TO) in the end of polar winters as the indicator of the cold accumulation in the troposphere and the type of its circulation is considered. The influence of TO over polar regions on the approach of early and late circulation reconstructions in the stratosphere and the following weather type in spring-summer season is concluded.     

The method of the medium-range forecast of air temperature in the area of the “Baikonur” cosmodrome

The statistical model of the forecast (complex postprocessing) of surface air temperature with the lead time up to eight days is constructed using the results of the integration of hydrodynamic atmospheric models. The model is adapted to the area of the “Baikonur” using the method of central typing that allows increasing the accuracy of operational forecasts. The analysis of climate characteristics needed for constructing the proper statistical model for this area is given using both observational data for recent 25 years and the data of WMO (from the All-Russian Research Institute of Hydro-meteorological Information-World Data Center). Computed are the estimates of the accuracy of operational forecasts.     

Characteristics of the Onset of the Asian Summer Monsoon and the Importance of Asian-Australian “Land Bridge”

Based on summarizing previous achievements and using data as long and new as possible, the onset characteristics of Asian summer monsoon and the role of Asian-Australian “land bridge” in the onset of summer monsoon are further discussed. In particular, the earliest onset area of Asian summer monsoon is comparatively analyzed, and the sudden and progressive characteristics of the onset of summer monsoon in different regions are discussed. Furthermore, the relationships among such critical events during the onset of Asian summer monsoon as the splitting of subtropical high belt over the Bay of Bengal (BOB), the initiation of convection over Indo-China Peninsula, the westward advance, reestablishment of South Asian High, and the rapid northward progression of convection originated from Sumatra in early summer are studied. The important impact of the proper collocation of the latent heating over Indo-China Peninsula and the sensible heating over Indian Peninsula on the splitting of the subtropical high belt, the deepening of BOB trough, the activating of Sri Lanka vortex (twin vortexes in the Northern and Southern Hemispheres), and the subsequent onset of South China Sea summer monsoon are emphasized.     

Predictability of the Atmosphere

This paper makes a review on the predictability of the atmosphere. The essential problems of predictability theory, i.e., how a deterministic system changes to an undeterministic system (chaos) and how is the opposite (order within chaos), are discussed. Some applications of predictability theory are given.     

Effect of the Interaction of Different Scale Vortices on the Structure and Motion of Typhoons

ＥｆｆｅｃｔｏｆｔｈｅＩｎｔｅｒａｃｔｉｏｎｏｆＤｉｆｆｅｒｅｎｔＳｃａｌｅＶｏｒｔｉｃｅｓｏｎｔｈｅＳｔｒｕｃｔｕｒｅａｎｄＭｏｔｉｏｎｏｆＴｙｐｈｏｏｎｓＣｈｅｎＬｉａｎｓｈｏｕ（陈联寿）（ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＭｅｔ６ｏｒｏｌｏｇｉｃ...     

The Variability of the Interannual Oscillations of the Indian Summer Monsoon Rainfall

A new method of analysis namely, Singular Spectrum Analysis (SSA) is applied to the Indian Summer Monsoon (June-September) Rainfall (ISMR) series. The method is efficient in extracting the statistically significant oscillations with periods 2.8 and 2.3 year from the white noise of the ISMR series. The study shows that 2.8 / 2.3 year cycle captures the variability of the ISMR related to Southern Oscillation / Quasi Biennial Oscillation. The temporal structure of these oscillations show that these are in phase in extreme (excess and drought) monsoon conditions as well as in El Nino Southern Oscillation (ENSO) years. Both these oscillations show minimum variability during the period 1920-1940 and there is an increasing trend in the variability of these oscillations in the recent decades. The study enables to obtain pure signal consisting of reconstructed time series using these two Oscillations, from the original white noise series.     

Spatiotemporal dynamics of the Urals’ climate in the second half of the 20th century

Dynamics of the surface air temperature and amount of precipitation in the Polar, Northern, and Southern Urals in the 20th century is analyzed. Charts of the temperature distribution in the Urals for the period from 1961 to 2000, taking into account the relief, are plotted in the geographical informational system on the basis of data of instrumental measurements at meteorological stations with the use of the multiple regression analysis and raster modeling. The northeastern direction of the warming gradient and increase of falling precipitations in the period under review is established. Time series of anomalies of the average annual air temperature and amount of precipitation in the 20th century at three meteorological stations, situated in the Polar, Northern, and Southern Urals, are analyzed. The tendency of the growth of anomalies of the average annual temperature and total amount of precipitation is revealed.