August: Legacy Effects

Author(s):  
Ellen Wohl

Emily Dickinson wrote a lovely poem using a brook as a metaphor for one’s interior life. The poem includes the lines: . . . And later, in August it may be, When the meadows parching lie, Beware lest this little brook of life Some burning noon go dry! . . . No chance of the little brook going dry if it runs through a beaver meadow. The movement of water across and through the North St. Vrain beaver meadow has slowed perceptibly by August. Some of the secondary channels barely flow and the main channel is easily crossed on foot. The water remains high in the main beaver pond, but few of the small dams winding across the meadow have water spilling over them. My feet are less likely to sink into wet black muck as I wander through the meadow, and even the moose tracks leave less of an imprint in the drying soil. Plenty of water remains, however, and the meadow is a much brighter shade of green than the adjacent, drier hill slopes. Many flowers remain in bloom across the meadow. Stalks bristling with the elaborate, richly pink blossoms of elephant’s head rise above standing water. Dusky purple monkshood flowers in slightly drier soil, as do the showy blue and white columbines. The blue bell-shaped flowers of harebell mark the driest sites. The late-summer flowers are joined now by the spreading tan or scarlet caps of fungi, as well as green berries on the ground juniper and kinnikinnick growing on the drier terrace beside the beaver meadow. Songbirds born this summer are fully feathered and capable fliers, and some of the birds have already left the meadow for the year. Early morning temperatures carry a hint of the coming autumn. The beaver kits grow steadily more capable, too, and by now they are used to foraging on their own. Presumably, this frees the breeding adult female for more time spent in dam and lodge repair or starting the food cache for the coming winter.

1991 ◽  
Vol 23 (1-3) ◽  
pp. 49-55
Author(s):  
E. H. baron van Tuyll van Serooskerken

An inventory is made of the effects of sea level rise and expected climatic change on the level of the district water authorities in the Netherlands and especially the “hoogheemraadschap” of Rhineland in the next 100-200 years. Special attention is paid to the effects on land utilization, coastal defence and water control. The first is hard to describe by lack of research, the second can already be determined in terms of cost; the third can be described in its effects on brackishness and water provision with indication of policies and measures to be taken. Preliminary conclusions are that larger efforts on coastal defence - even with present techniques - will be a realistic answer in terms of cost. The foreseen increase of brackishness in area and salt concentration, will give a significant extra need for fresh water. High cost and even higher risks have to be expected with regard to measures to neutralize the effects of a water surplus in winter and a growing water shortage in (late) summer, while the cost will further grow. Because of the effect a larger area must be drained off and water has to be raised higher as the Netherlands will sink in relation to the North Sea.


1886 ◽  
Vol 3 (9) ◽  
pp. 398-402

The “Lake District” of the North Island is too well known to all students of volcanic phenomena, especially of that branch comprising hydrothermal action, to need a detailed description. It will be sufficient to say that it forms a belt, crossing the island from north-east to south-west, and forms a portion of the Middle and Upper Waikato Basins of Hochstetter. The district has been recently brought into prominent notice by the disastrous eruption of Mount Tarawera, very full accounts of which have appeared in New Zealand papers lately received. The eruption commenced in the early morning of Thursday, June 10th, but premonitory symptoms showed themselves a few days before in a tidal wave, three feet high, on Lake Tarawera, great uneasiness of the springs at Ohinemutu, and the reported appearance of smoke issuing from Euapehu, the highest of the great trachytic cones at the extreme south-westerly end of the system. The belt of activity extends from Mount Tongariro at the one end to White Island, in the Bay of Plenty, at the other, a distance of about 150 miles. White Island has undergone considerable change from volcanic action during recent years, and Tongariro was last in eruption in July, 1871; whilst its snowclad sister cone Euapehu has never manifested volcanic action within the historic period until now. This wide zone in the centre of the North Island has, ever since the arrival of the Maoris, been the scene of such extraordinary phenomena, that it has of late been the resort of visitors from all quarters of the globe.


2018 ◽  
Vol 18 (19) ◽  
pp. 14637-14651 ◽  
Author(s):  
Yingjie Zhang ◽  
Wei Du ◽  
Yuying Wang ◽  
Qingqing Wang ◽  
Haofei Wang ◽  
...  

Abstract. The North China Plain (NCP) has experienced frequent severe haze pollution events in recent years. While extensive measurements have been made in megacities, aerosol sources, processes, and particle growth at urban downwind sites remain less understood. Here, an aerosol chemical speciation monitor and a scanning mobility particle sizer, along with a suite of collocated instruments, were deployed at the downwind site of Xingtai, a highly polluted city in the NCP, for real-time measurements of submicron aerosol (PM1) species and particle number size distributions during May and June 2016. The average mass concentration of PM1 was 30.5 (±19.4) µg m−3, which is significantly lower than that during wintertime. Organic aerosols (OAs) constituted the major fraction of PM1 (38 %), followed by sulfate (25 %) and nitrate (14 %). Positive matrix factorization with the multilinear engine version 2 showed that oxygenated OA (OOA) was the dominant species in OA throughout the study, on average accounting for 78 % of OA, while traffic and cooking emissions both accounted for 11 % of OA. Our results highlight that aerosol particles at the urban downwind site were highly aged and mainly from secondary formation. However, the diurnal cycle also illustrated the substantial influence of urban emissions on downwind sites, which are characterized by similar pronounced early morning peaks for most aerosol species. New particle formation and growth events were also frequently observed (58 % of the time) on both clean and polluted days. Particle growth rates varied from 1.2 to 4.9 nm h−1 and our results showed that sulfate and OOA played important roles in particle growth during clean periods, while OOA was more important than sulfate during polluted events. Further analyses showed that particle growth rates have no clear dependence on air mass trajectories.


2002 ◽  
Vol 3 (1) ◽  
pp. 5 ◽  
Author(s):  
V. ZERVAKIS ◽  
D. GEORGOPOULOS

The combination of two research projects offered us the opportunity to perform a comprehensive study of the seasonal evolution of the hydrological structure and the circulation of the North Aegean Sea, at the northern extremes of the eastern Mediterranean. The combination of brackish water inflow from the Dardanelles and the sea-bottom relief dictate the significant differences between the North and South Aegean water columns. The relatively warm and highly saline South Aegean waters enter the North Aegean through the dominant cyclonic circulation of the basin. In the North Aegean, three layers of distinct water masses of very different properties are observed: The 20-50 m thick surface layer is occupied mainly by Black Sea Water, modified on its way through the Bosphorus, the Sea of Marmara and the Dardanelles. Below the surface layer there is warm and highly saline water originating in the South Aegean and the Levantine, extending down to 350-400 m depth. Below this layer, the deeper-than-400 m basins of the North Aegean contain locally formed, very dense water with different θ /S characteristics at each subbasin. The circulation is characterised by a series of permanent, semi-permanent and transient mesoscale features, overlaid on the general slow cyclonic circulation of the Aegean. The mesoscale activity, while not necessarily important in enhancing isopycnal mixing in the region, in combination with the very high stratification of the upper layers, however, increases the residence time of the water of the upper layers in the general area of the North Aegean. As a result, water having out-flowed from the Black Sea in the winter, forms a separate distinct layer in the region in spring (lying between “younger” BSW and the Levantine origin water), and is still traceable in the water column in late summer.


2012 ◽  
Vol 8 (3) ◽  
pp. 1885-1914
Author(s):  
D. Xiao ◽  
P. Zhao ◽  
Y. Wang ◽  
X. Zhou

Abstract. Using an intermediate-complexity UVic Earth System Climate Model (UVic Model), the geographical and seasonal implications and an indicative sense of the historical climate found in the δ18O record of the Guliya ice core (hereinafter, the Guliya δ18O) are investigated under time-dependent orbital forcing with an acceleration factor of 100 over the past 130 ka. The results reveal that the simulated late-summer (August–September) Guliya surface air temperature (SAT) reproduces the 23-ka precession and 43-ka obliquity cycles in the Guliya δ18O. Furthermore, the Guliya δ18O is significantly correlated with the SAT over the Northern Hemisphere (NH), which suggests the Guliya δ18O is an indicator of the late-summer SAT in the NH. Corresponding to the warm and cold phases of the precession cycle in the Guliya temperature, there are two anomalous patterns in the SAT and sea surface temperature (SST) fields. The first anomalous pattern shows an increase in the SAT (SST) toward the Arctic, possibly associated with the joint effect of the precession and obliquity cycles, and the second anomalous pattern shows an increase in the SAT (SST) toward the equator, possibly due to the influence of the precession cycle. Additionally, the summer (winter) Guliya and NH temperatures are higher (lower) in the warm phases of Guliya late-summer SAT than in the cold phases. Furthermore, the Guliya SAT is closely related to the North Atlantic SST, in which the Guliya precipitation may act as a "bridge" linking the Guliya SAT and the North Atlantic SST.


2020 ◽  
Vol 33 (1) ◽  
pp. 201-212
Author(s):  
G. Wolf ◽  
A. Czaja ◽  
D. J. Brayshaw ◽  
N. P. Klingaman

AbstractLarge-scale, quasi-stationary atmospheric waves (QSWs) are known to be strongly connected with extreme events and general weather conditions. Yet, despite their importance, there is still a lack of understanding about what drives variability in QSW. This study is a step toward this goal, and it identifies three statistically significant connections between QSWs and sea surface anomalies (temperature and ice cover) by applying a maximum covariance analysis technique to reanalysis data (1979–2015). The two most dominant connections are linked to El Niño–Southern Oscillation and the North Atlantic Oscillation. They confirm the expected relationship between QSWs and anomalous surface conditions in the tropical Pacific and the North Atlantic, but they cannot be used to infer a driving mechanism or predictability from the sea surface temperature or the sea ice cover to the QSW. The third connection, in contrast, occurs between late winter to early spring Atlantic sea ice concentrations and anomalous QSW patterns in the following late summer to early autumn. This new finding offers a pathway for possible long-term predictability of late summer QSW occurrence.


2003 ◽  
Vol 93 (1) ◽  
pp. 55-63 ◽  
Author(s):  
A. Raman ◽  
T.M. Withers

AbstractAn Australian gall-inducing eulophid,Ophelimus eucalypti(Gahan) was first recorded on the foliage ofEucalyptus botryoidesafter it invaded New Zealand in 1987. It has spread throughout the eucalypt plantations in the North Island and in the northern parts of the South Island affecting several species ofEucalyptusin the section Transversaria (subgenusSymphyomyrtus). Because gall-inducing insects usually have extremely narrow host ranges,O. eucalyptithat induces galls onE. salignaandE. botryoidesis currently recognized as a biotype,O. eucalypti(Transversaria). Heavily galled leaves abscise from the plant. Repeated defoliation led to widespread die-back of susceptible eucalypt species in the 1990s. Female larvae ofO. eucalyptiinduce circular, protruding galls on the leaves ofE. botryoidesandE. saligna, whereas the males induce pit galls on the same species. The biology ofO. eucalyptifemales and the development of their galls are described. Adult femaleO. eucalyptiantennate the leaf surface before inserting the ovipositor (otherwise concealed within the metasomal apex) into the young host leaf. The egg is inserted at approximately 45° and discharged between differentiating palisade cells. Callus-type cells surround the egg chamber, but cytologically specialized nutritive cells appear once the egg hatches and the larva begins to feed. The gall also differentiates a multi-layered sclerenchymatous tissue around the nutritive tissue. After feeding for many months, the larva pupates and the active nutritive tissue degenerates. The adult wasp emerges after cutting an exit hole through to the outside of the gall. Abscission of heavily galled leaves results in widespread defoliation and loss of growth and vigour in susceptible trees in New Zealand.


Author(s):  
Fabienne Delfour

Hawaiian spinner dolphins (Stenella longirostris) feed offshore at night on mesopelagic prey and move to protected shallow waters in early morning to rest. We hypothesized that this behaviour would make them particularly sensitive to anthropogenic factors in these rest areas and would affect their overall behaviour and their population frequency. To test our hypothesis we collected data in a known rest area along the north-west coast of the island of Oahu during August of 2001, 2002 and 2003. Using land- and water-based surveys, we evaluated dolphin group size, counted boats, kayaks and swimmers in the vicinity of the dolphins (<40 m) and reported any changes in dolphin behaviour. Our results demonstrated a stable dolphin habitat frequency over the three summers, which emphasizes the critical value of this rest area for this spinner dolphin population. The results also showed an increase in dolphin-oriented activities, but we could not draw any definitive conclusion on their real impacts on spinner dolphin ecology and ethology.


1973 ◽  
Vol 30 (7) ◽  
pp. 917-925 ◽  
Author(s):  
J. O. Blanton

The rate of change of heat contents in the lakes and the relative ability of each lake to transfer heat vertically to warm its hypolimnion was investigated. Rates of warming of hypolimnion water ranged from 0.06 C/month in Okanagan to 0.54 C/month in the north basin of Osoyoos. All lakes reached maximum static stability through the thermocline in late August except for Osoyoos (N), which reached its maximum somewhat earlier. Maximum heat content ranged from 18,100 cal/cm2 in Wood Lake to 33,300 cal/cm2 in Lake Okanagan. Maximum values of heat content were observed in late August in all lakes.There is a direct relation between the hypolimnetic warming rates and the maximum observed stability in the thermocline regions of all the lakes. However, the relatively low rate of Lake Wood indicates that there is an external cooling source such as groundwater influx. The late summer increase in volume of the epilimnion in Wood and the corresponding entrainment of nutrients from the hypolimnion to the epilimnion appear to control the amount of production observed at that time.


1947 ◽  
Vol 15 (1-2) ◽  
pp. 80-88 ◽  
Author(s):  
C. R. Barnicoat

1. Chemical estimations of carotene and vitamin A in New Zealand butters from two of the principal butter-making districts of the North Island during the seasons 1935–6 show that the total vitamin A potency was fairly high.2. There were seasonal variations apparently due to nutritional rather than physiological causes. The minimum values (33–37 i.u./g. butterfat) for total vitamin A were found in late summer (February) at the time when the pasture normally tends to dry up, while the peak values (42–53 i.u./g. butterfat) occurred in late winter and spring (July-October). The variations in vitamin A potency with season were in the opposite direction to the variations recorded in the literature for Europe and America. The difference is no doubt due to the practice of stall-feeding in these countries in contrast with the all-the-year-round grazing commonly practised on dairy farms in New Zealand. The spring flush of grass is also later in the season in Europe than in New Zealand.3. The more deeply-coloured Jersey butterfat was only slightly richer in total vitamin A potency than Friesian butterfat.4. Contents of carotene and vitamin A in the fat of colostrum were very high, but reached normal values within 4 or 5 days after parturition.


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