Top PDF Phenological changes in the southern hemisphere.

Phenological changes in the southern hemisphere.

Phenological changes in the southern hemisphere.

Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand), South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias), although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa) and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially and logistically supported.
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Halophila baillonis Ascherson: first population dynamics data for the Southern Hemisphere

Halophila baillonis Ascherson: first population dynamics data for the Southern Hemisphere

The plants have fragile rhizomes (0.6-1.5 mm in diameter), with 1 root at each node, and internodes 9-23 mm long; stems 10-24 mm long, erect, bearing (in the middle portion) 2 scales that are obovate, keeled, glabrous, 3-5 mm long; 4 leaves are arranged in a pseudo-whorl at the tip of the stem. Blades oblong, ovate, elliptic to lanceolate, 7-12 mm long, 3-4 mm wide, with 3-5 unbranched cross-veins on each side of the pronounced midrib, margin finely serrulate (Fig. 1). Flowers and fruits were not seen. Shoot density varied from 133 to 2,520 shoots.m -2 ; aboveground biomass varied
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Temperature changes of the past 2000 yr in China and comparison with Northern Hemisphere

Temperature changes of the past 2000 yr in China and comparison with Northern Hemisphere

face temperature variations in China over the last two millennia using natural proxies, such as tree rings, ice cores, lake sediments, and stalagmites, as well as archaeolog- ical evidence and historical documents (Chu, 1973; Shao and Wu, 1994; Yao et al., 1996; Zhang, 1996). Based on these temperature proxies, two composite temperature reconstructions covering the whole of China for the past 2000 yr were derived by Yang

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A Century of Tuberculosis Epidemiology in the Northern and Southern Hemisphere: The Differential Impact of Control Interventions.

A Century of Tuberculosis Epidemiology in the Northern and Southern Hemisphere: The Differential Impact of Control Interventions.

Underlying socioeconomic, biological and environmental conditions could make the popu- lation of Cape Town more at risk of TB than that of New York and London. Cape Town has high inequality with the most recent equity index estimated at 0.22 compared to 0.50 in New York and 0.79 in London [47]. Lower socioeconomic circumstances are associated with crowd- ing and malnutrition, known risk factors for TB transmission and progression to active disease. The effective contact number in Cape Town might have remained high, where it declined dra- matically in London over the last century [48]. During that time average household sizes in the United States and Britain decreased 2-fold [49, 50]. Historical data on average household size in Cape Town are not available, but it is currently higher in Cape Town than in New York and London (3.5 versus 2.4 and 2.5) [50–52]. The increased in-migration may have caused more crowded conditions, with increased spread of TB as a consequence. A higher genetic suscepti- bility for TB infection and disease is unlikely considering that TB has affected all population groups in Cape Town at different times throughout the century. Finally, there could be envi- ronmental differences between Cape Town and the northern cities which facilitate TB transmission.
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Energetic particle precipitation in ECHAM5/MESSy1 – Part 1: Downward transport of upper atmospheric NO<sub>x</sub> produced by low energy electrons

Energetic particle precipitation in ECHAM5/MESSy1 – Part 1: Downward transport of upper atmospheric NO<sub>x</sub> produced by low energy electrons

F05, using data from the MIPAS instrument on board ENVISAT. F05 presents results for the Southern Hemisphere winter 2003. Since these measurements did not form a basis for the parameterization in any form, the comparison will be independent. In order to ease a comparison with F05, potential temperature was chosen as vertical coordinate. This also allowed a consistent transformation to equivalent latitude (Nash

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Detection of influenza B lineages from 2001 to 2013 in a tertiary hospital in the city of São Paulo, Brazil

Detection of influenza B lineages from 2001 to 2013 in a tertiary hospital in the city of São Paulo, Brazil

Surveillance from 2001-2011 in the United States of America and Europe showed that the chance of a correct matching between vaccine and circulating influenza B lineages was 50% (Ambrose & Levin 2012). Conse- quently, the influenza vaccination was less effective during mismatched seasons. Information about the cir- culation of these lineages is important to assess the need for a quadrivalent influenza vaccine. The objective of this study was to describe the influenza B circulation in different patient groups from a tertiary hospital of the largest city in the Southern Hemisphere from 2001-2013 and the lineage differentiation of this virus using a sensi- tive and lineage specific real-time reverse transcription- polymerase chain reaction (RT-PCR) method.
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Rev. bras. meteorol.  vol.24 número1

Rev. bras. meteorol. vol.24 número1

Previous studies have already indicated the interaction of the SaM phases with the South america atmospheric circulation and in particular their inluence on the precipitation patterns (e.g., Silvestri and Vera 2003; carvalho et al 2005). this work provides further evidence of this relationship showing a link between the Southern hemisphere cyclone activities with SaM phases. the variability of the South american summer monsoon and the SaM phase is suggested and it also raised some interesting questions. for instance, is the South american llJ or the Sacz modulated by the SaM phases? is there any relationship between rainfall extreme events over the southern Brazil and the SaM? however from the present study other important questions were not discussed, for instance, why the precipitation anomalies over South america are not symmetric between the SaM phases? of course, the atmospheric general circulation is non linear but how is it possible to measure such differences? these are just a few questions that still need to be investigated.
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SURFACE OZONE CONCENTRATIONS AND THE METEOROLOGICAL CONDITIONS AT AN URBAN TROPICAL SITE IN THE SOUTHERN HEMISPHERE

SURFACE OZONE CONCENTRATIONS AND THE METEOROLOGICAL CONDITIONS AT AN URBAN TROPICAL SITE IN THE SOUTHERN HEMISPHERE

A natural catalytic cycle based on the nitrates produces ozone through the photolysis of NO2 and destroys it in the reaction with NO. However, surface ozone also results from anthropogenic sources. Highs in surface ozone concentration (SOC) – or, al- ternatively, the ozone mixing ratio – come out in the presence of solar radiation (λ < 420 nm) plus primary pollutants like the volatile organic compounds (VOCs) from natural and anthro- pogenic sources and carbon monoxide (CO) and the nitrates from power plants based on fossil fuel and car exhausts (Atkinson, 2000). Meteorological and geophysical parameters like temper- ature, relative humidity (or just humidity), cloud cover, precipi- tation, winds, aerosols, and plumes of smoke also play impor- tant roles in the determination of SOC (Kim & Newchurch, 1998; Camalier et al., 2007; Duncan et al., 2008; Flynn et al., 2010). Surface ozone is a toxic and powerful oxidant leading to deleteri- ous effects on materials and life (Tilton, 1989; Lippmann, 1991; McConnell et al., 2002; Bell et al., 2004; Pandrangi & Morri- son, 2008). The limits for human exposure to SOC vary world- wide depending on the local legislation (Meleux et al., 2007; Beig et al., 2008; Duncan et al., 2008; Shan et al., 2008), which are generally based on the World Health Organization recommenda- tions (WHO, 1987). In Brazil, a resolution (No. 03 of June 28 of 1990, www.mma.gov.br/port/conama/res/res90/res0390.html) of the Conselho Nacional do Meio Ambiente (CONAMA) states an hourly averaged limit of 160μg m –3 that must not be exceeded
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Northern Hemisphere control of deglacial vegetation changes in the Rufiji uplands (Tanzania)

Northern Hemisphere control of deglacial vegetation changes in the Rufiji uplands (Tanzania)

mental responses to YD are consistent with the heterogeneous vegetation observed in our record suggesting that the YD signal from this area is ambiguous which corrob- orate previous findings in the Indo-Pacific Warm Pool (Denniston et al., 2013; Dubois et al., 2014) where YD is also not well defined. Therefore, our data suggest that H1 had a greater influence on East African hydrologic conditions than the YD, another North

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Quantitative assessment of Southern Hemisphere ozone in chemistry-climate model simulations

Quantitative assessment of Southern Hemisphere ozone in chemistry-climate model simulations

To assess the robustness of our model ranking we perform several sensitivity tests. The sensitivity of the ranking to the choice of the reference data sets is assessed by calculating the performance indices using the individual reference data sets separately. Since for the Randel and Hassler data sets we do not have corresponding total ozone timeseries, these data sets are used in combination with the TOMS/SBUV data set. To study sensitivity of the results to sampling errors we use ad- ditional runs available for SOCOL, MRI, and WACCM. The calculations were repeated for two additional simulations for each of these models. Also we apply small modifications to the original diagnostics, which include restricting the domain to above 200 hPa, weighting the ozone profile errors accord- ing to the mass or geometric thickness of the corresponding layer, or calculating the total ozone climatology diagnostic over the SH only. The performance indices calculated in these sensitivity tests are shown in Fig. 11 and provide an estimate of the ranking uncertainty. The changes in the per- formance indices in these experiments are up to 15% (about
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Quasi-stationary waves in the Southern Hemisphere during El Niño and La Niña events

Quasi-stationary waves in the Southern Hemisphere during El Niño and La Niña events

waves 2 and 3 have much less amplitude. Monthly variation of the amplitude of QS wave 1 shows that it is highest in Oc- tober, particularly in the upper troposphere and stratosphere. To examine the QS wave propagation Plumb’s methodol- ogy is used. A comparison of Eliassen-Palm fluxes for El Ni˜no and La Ni˜na events showed that during El Ni˜no events there is a stronger upward and equatorward propagation of QS waves, particularly in the austral spring. Higher upward propagation indicates higher energy transport. A clear wave train can be identified at 300 hPa in all the seasons except in summer. The horizontal component of wave activity flux in the El Ni˜no composite seems to be a Rossby wave prop- agating along a Rossby wave guide, at first poleward until it reaches its turning latitude in the Southern Hemisphere mid- latitudes, then equatorward in the vicinity of South America. The position of the center of positive anomalies in the aus- tral spring in the El Ni˜no years over the southeast Pacific, near South America, favors the occurrence of blocking highs in this region. This agrees with a recent numerical study by Renwick and Revell (1999).
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Southern westerlies in LGM and future (RCP4.5) climates

Southern westerlies in LGM and future (RCP4.5) climates

ulations, we have chosen to use the 850 hPa zonal wind. This level characterises the eddy-driven jet and its fluctuations while remaining above the surface boundary layer. The wind speed is larger at the tropopause level, but the upper-level jet mixes driving by eddies and the Hadley cell, and its position is less meaningful: a strong subtropical jet can hide changes in the near-surface winds, which are the ones interacting with the

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IMPACTS OF SOUTHERN HEMISPHERE WESTERLIES ON THE BRAZIL CURRENT AT 30ºS

IMPACTS OF SOUTHERN HEMISPHERE WESTERLIES ON THE BRAZIL CURRENT AT 30ºS

The BC is the western boundary current into the South Atlantic Subtropical Gyre, which flows southward along the Brazilian coast and feeds the upper branch of the Atlantic Meridional Overturning Circulation (AMOC). While it flows south, the BC carries warmer subtropical waters to high latitudes where it collides with the northward colder waters from the Malvinas Current (MC) between 33ºS–40ºS (Matano et al., 1993), in the region called the Brazil-Malvinas Confluence (BMC). The BC transport is considered smaller and shallower than other western boundary currents, although it increases as it runs southward (Gordon & Greengrove, 1986; Stramma, 1989; Stramma et al., 1990; Pickard & Emery, 2016). Stramma (1989) used historical hydrographic data to compute geostrophic transports between 5–6.5 Sv (1 Sv = 1x10 6 m 3 s −1 in the upper 500 m near 20ºS.
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The impact of soil uptake on the global distribution of molecular hydrogen: chemical transport model simulation

The impact of soil uptake on the global distribution of molecular hydrogen: chemical transport model simulation

and the lifetime is longer than the timescale of transport and mixing, the H 2 concen- tration is well mixed. The homogeneous distribution also results in smaller synoptic variation (see the result of South Pole (SPO) in Fig. 4), expect at CGO for reasons discussed above. Novelli et al. (1999) and Hauglustaine and Ehhalt (2002) pointed out that the main influencing factor of the seasonal cycle in the Southern Hemisphere is

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Índices de monção de verão para o Hemisfério Sul simulados pelos modelos do CMIP

Índices de monção de verão para o Hemisfério Sul simulados pelos modelos do CMIP

Extensive studies have been conducted to examine the skill of climate models in simulating the variability of summer monsoon rainfall based in indices and future projections (Wang et al. 2014; Sharmila et al. 2015; Parth Sarthi et al. 2015;). However, most efforts focuses on regional monsoon domains for the Northern Hemisphere, over Asian and Indian monsoon; much less modeling studies involving monsoon indices for the Southern Hemisphere has been devoted. Some studies suggest changes by the end of the 21st century, such as increase significantly of the precipitation over East Asian summer monsoon (6.4 %/ºC), while in AUS summer monsoon will increase 2.6%/ºC (Wang et al. 2014). The land monsoon domain over Asia will expand with 10.6% in extent, and also the increase of the percentage of local summer rainfall including some parts of the Asia, Africa, Australia, South America monsoon (Lee and Wang 2014). Monsoon retreat dates will delay, onset dates will either advance or no change, prolonging the monsoon seasons (Kitoh et al. 2013). In addition, surface evaporation will increases at a higher rate, resulting in a larger increase rainfall based in thermodynamic and dynamic effects (Endo and Kitoh 2014). Furthermore, the increase of the global monsoon precipitation can be attributed to increase of moisture convergence due increase evaporation and water vapor (Kitoh et al. 2013; Yim et al. 2014).
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Deriving mass balance and calving variations from reanalysis data and sparse observations, Glaciar San Rafael, northern Patagonia, 1950–2005

Deriving mass balance and calving variations from reanalysis data and sparse observations, Glaciar San Rafael, northern Patagonia, 1950–2005

Abstract. Mass balance variations of Glaciar San Rafael, the northernmost tidewater glacier in the Southern Hemisphere, are reconstructed over the period 1950–2005 using NCEP- NCAR reanalysis climate data together with sparse, local historical observations of air temperature, precipitation, ac- cumulation, ablation, thinning, calving, and glacier retreat. The combined observations over the past 50 yr indicate that Glaciar San Rafael has thinned and retreated since 1959, with a total mass loss of ∼22 km 3 of ice eq. Over that period, ex- cept for a short period of cooling from 1998–2003, the cli- mate has become progressively warmer and drier, which has resulted primarily in pervasive thinning of the glacier surface and a decrease in calving rates, with only minor acceleration in retreat of the terminus. A comparison of calving fluxes derived from the mass balance variations and from theoret- ical calving and sliding laws suggests that calving rates are inversely correlated with retreat rates, and that terminus ge- ometry is more important than balance fluxes to the termi- nus in driving calving dynamics. For Glaciar San Rafael, regional climate warming has not yet resulted in the signifi- cant changes in glacier length seen in other calving glaciers in the region, emphasizing the complex dynamics between climate inputs, topographic constraints and glacier response in calving glacier systems.
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The ASSET intercomparison of stratosphere and lower mesosphere humidity analyses

The ASSET intercomparison of stratosphere and lower mesosphere humidity analyses

Abstract. This paper presents results from the first de- tailed intercomparison of stratosphere-lower mesosphere wa- ter vapour analyses; it builds on earlier results from the EU funded framework V “Assimilation of ENVISAT Data” (AS- SET) project. Stratospheric water vapour plays an impor- tant role in many key atmospheric processes and therefore an improved understanding of its daily variability is desir- able. With the availability of high resolution, good quality Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) water vapour profiles, the ability of four different atmospheric models to assimilate these data is tested. MI- PAS data have been assimilated over September 2003 into the models of the European Centre for Medium Range Weather Forecasts (ECMWF), the Belgian Institute for Space and Aeronomy (BIRA-IASB), the French Service d’A´eronomie (SA-IPSL) and the UK Met Office. The resultant middle atmosphere humidity analyses are compared against inde- pendent satellite data from the Halogen Occultation Exper- iment (HALOE), the Polar Ozone and Aerosol Measurement (POAM III) and the Stratospheric Aerosol and Gas Experi- ment (SAGE II). The MIPAS water vapour profiles are gen- erally well assimilated in the ECMWF, BIRA-IASB and SA systems, producing stratosphere-mesosphere water vapour fields where the main features compare favourably with the independent observations. However, the models are less ca- pable of assimilating the MIPAS data where water vapour values are locally extreme or in regions of strong humid- ity gradients, such as the southern hemisphere lower strato- sphere polar vortex. Differences in the analyses can be at- tributed to the choice of humidity control variable, how the background error covariance matrix is generated, the model
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A common feature in latitudinal dependence of different geophysical processes occurring on the rotating Earth

A common feature in latitudinal dependence of different geophysical processes occurring on the rotating Earth

The latitudinal distribution of the Earth hotspot relative number according to the work of Courtillot et al. (2003) is presented in Fig. 7b. The common number of studied objects is equal to 49. In this case the latitudinal distribution of the Earth hotspot number shows clearly expressed peaks in mid- dle latitudes of the Northern Hemisphere and the Southern Hemisphere (30–40 ◦ N and 20–30 ◦ S), local minimum near the Equator (0–20 ◦ N), zero values in the high latitude in the Southern Hemisphere and negligible values in the high lati- tude in the Northern Hemisphere. These results are in good agreement with our results presented above. It should be noted that the hotspot latitudinal distributions are asymmet- ric with respect to the Equator; they are shifted northwards as the latitudinal distributions of the EQ density and released energy.
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Subauroral red arcs as a conjugate phenomenon: comparison of OV1-10 satellite data with numerical calculations

Subauroral red arcs as a conjugate phenomenon: comparison of OV1-10 satellite data with numerical calculations

Fig. 7. The time variations of the modeled integral intensities at 630 nm in the SAR-arc regions in the northern (bottom panel ) and southern (top panel ) hemispheres at L ˆ 2:72 for the recovery phase of the 16±17 February 1967 magnetic storm. Crosses represent the integral intensities at 630 nm in the SAR-arc regions measured by the OV1±10 photometer at 21:47 LT (northern hemisphere) and 22:15 LT (southern hemisphere) on 16 February 1967. The solid, dashed and dashed-dotted lines are the calculated integral intensities from model A, B, and C of the rate coecients of O ‡ … 4 S† ions with the vibrationally excited nitrogen molecules and quenching of O ‡ … 2 D† by atomic oxygen described in the Appendix. The modeled results were obtained using the non-Boltzmann populations of the ®rst ®ve vibrational levels by solving the N 2 … j ˆ 1±5† time-dependent
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Geometrical and optical parameters of  Tropopause Cirrus Clouds in the Southern Hemisphere

Geometrical and optical parameters of Tropopause Cirrus Clouds in the Southern Hemisphere

Clouds measurements derived from lidar systems at various height regions have attracted increasing attention recently due to their role in modulating the fluxes of incoming short wave and outgoing long- wave radiation (Wylie et al., 1994). Lidars are very useful in deriving the optical properties of the clouds. The optical extinction of clouds is an important key parameter in radiative transfer analysis and therefore considerable efforts have been put in its retrieval (Platt and Dilley, 1984). On the other hand, the sign and magnitude of cirrus radiative forcing depends on cloud altitude and the cirrus optical depth which is a function of the effective ice crystal radius, and the number concentration of ice crystals (Fu and Liou, 1993). Lidar systems constitute a powerful tool to analyse the temporal and spatial evolution of the atmospheric aerosols as well as chemical and physical properties of clouds components (Wang et al., 2005).
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