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Joined: 15 May 2007
Posts: 969
Location: north-east victoria
Posted: Wed Jan 16, 2008 9:44 pm Post Subject:
a meteorological question for you, Hector
this morning there were vigorous cumulus towers, which were apparent from first light
normally thunderstorms come through from noon to about 10 pm, mostly around 4-7 pm
early morning storms like these are rare, and it got me puzzled about the mechanism inside these clouds
there were a couple of small, very intense thunderstorms which passed close during the dawn, and about a dozen other wannabe thunderheads about, over an hour or so
not much rain associated with them, and they seemed to be quite high.......lots of altitude to the bases of the rain clouds
how do these things get up and running , without the rising warm air mechanism to drive them?
steve, let's assume that the lower part of the troposphere around where you live was already conditionally unstable and ripe for a bit of convection yesterday morning. "Conditionally unstable" means that the lower atmosphere is stable (there will be no convection) provided the water vapor in it does not condense (and release the latent heat of condensation). Put another way, it will be unstable on the condition that the water vapor condenses.
For vigorous convection, the vertical temperature profile above the convection base needs to be right to realise plenty of energy (which will come from the release of latent heat).
How to get the water vapour to condense. The only way to do it is to cool the air some how. The way to do that in place, is to get it to rise; because rising air cools. There are several ways that can happen. One is by solar heating of the ground; the air in contact with the ground warms up, rises and cools. (More heating of the ground, more air rising and cooling, higher and higher. Eventually, self sustaining convection.) There are several other ways:
wind against orography (mountains)
large scale, synoptically forced lift (vorticity and/or thermal advections - these are to do with the shape of the upper wind flow)
local convergence in low level wind flows
ascent of warm air at a frontal surface
wave motion (eg. gravity waves)
mechanical turbulence near the surface
These (and surface heating by the sun) are called "triggers" for the convection. If you have conditional instability, you need a trigger to set off the convection by raising (cooling) the air until it condenses. No trigger, then no convection, and no cumulus clouds. In weather forecasting, identifying the areas of instability (and its magnitude) as well as identifying a trigger mechanism are the keys to the successful forecasting of convection and the consequent showers, thunderstorms, etc. Misidentification or misplacement of a trigger mechanism is the major cause of convection forecast failures - occurring unexpectedly or not occurring at all.
Any of those triggers (listed) or a combination of more than one of them could have have been the trigger for the convection you saw.
The high cloud bases would have been caused by the low humidity of the air being lifted. With dryish air, it needs to be lifted (cooled) a lot before it finally reaches 100% humidity and condenses... a cumulus base of 5000 - 7000 feet is not uncommon in Australia.
Well, that's a once over lightly. If there are any questions to clarify some aspect, ask away.
Joined: 15 May 2007
Posts: 969
Location: north-east victoria
Posted: Thu Jan 17, 2008 11:47 pm Post Subject:
thanks, Hector, i'll chew through this more slowly tomorow
lots of factors to consider, i suppose many or even most could be working at once
still a bit of a challenge, in this instance there were little pockets in all sorts of terrain, all trying to make thunderheads......the two successful ones , predictably, were drawn down the high ridge, but the little ones out over the plain were in pockets, dotted around
i intuitively feel there is a large electrical force involved in their formation
Joined: 15 May 2007
Posts: 969
Location: north-east victoria
Posted: Fri Jan 18, 2008 9:43 am Post Subject:
vorticity and thermal advection.......sounds like a venturi effect , like the gizzmo that sucks water out of a dinghy , once it's moving fast enough ?? but how does this work by virtue of wind shape in the upper troposphere? and in this context, what does "synoptically " mean, please ?
local convergence, where two masses of air are pushed together, and create a pressure rise, and heat?
ascent of warm air at a frontal surface.......this is where a cold front shaped like a wedge of cold air, like an axe-head lying flat, pushes the air in front of it up?
now , you mention gravity waves next, which makes me think you don't have too much faith in all those other mechanisms.......(as far as the activity a couple of days ago is concerned, i don't either ! )
now, as i understand it, gravity waves are a theory that took physicists an immense amount of puffing and blowing , over a couple of centuries ,to formulate in such a way as to allow generations of academics to derive a living from them >? (not earn a living, mind you, just derive one) correct me if i'm wrong, but these "gravity waves" are still speculation, and the medium through which they allegedly work is still a complete unknown, and in any case, with respect to the mass involved in a wee bit of an air column, they are about as potent as the proverbial bubble on a puddle of piss?
mechanical turbulence clearly will function more as a trigger than as an engine
so, what about the electrical component? once these towers of warm air are rushing upwards, and your adiabatic cold winds are howling down the guts, you get , as in this case, potent lightning . my question is, does the voltage difference come from the action of air, or does the voltage difference have something to do with setting the air in motion??
it seemed to me, that given the apparently peaceful state of things on the ground, and the apparently unremarkable conditions in the troposphere, the fact that these thunderheads were trying to spring up all over the place, and two of them succeeded, (producing many spot-fires from lightning strikes in the next valley) in forming up at a great height, when the triggers and conditions you mentioned were not abundantly in evidence, there must be some other force at work ?
i've watched these things on the radar a lot, also
sometimes they form in lines, sometime in apparently random spotting
sometimes they move, sometimes they sit still for half a day
Vorticity advection: If there is horizontal wind shear (the wind speed is changing as you move across the flow), or if there is curvature, then there is vorticity in the wind flow. If this patch of vorticity is moving with the flow, then there is vorticity advection there. Cyclonic (rotation in the same sense as the rotation of the earth) vorticity advection induces vertical motion upwards.
Thermal advection: If the wind is blowing across isotherms (lines connecting equal temperature) then there is thermal advection. Warm (positive) advection indices vertical motion upwards.
Convergence: Where the wind flow is converging (from different directions, but not necessarily opposite) near the ground, there there has to be vertical motion. The air can't go into the ground, and does not compress and increase in density, and does not vanish; the only way out is up.
Your analogy of the wedge/axhead is a good one.
Gravity waves (in the meteorological context): is a wave motion of air in the atmosphere where the restoring force is buoyancy/gravity. Examples: ocean swell, mountain waves (also called lee waves).
"Mechanical" turbulence is turbulence induced by obstacles like trees and other vegetation, hills, buildings, sea and swell waves, etc. This is to distinguish this type of turbulence from the type resulting from the break down of laminar flow in the free atmosphere (due to instability of the flow itself).
The separation and build up of electric charge in convection is still not fully understood by the cloud physicists. They do know it has to do with the presence of ice or the freezing of water droplets, and their movement in the up/down drafts. When there is no freezing, there is no lightning.
"the apparently peaceful state of things on the ground, and the apparently unremarkable conditions in the troposphere": It is not possible to "see" instability or convergence until it manifests in some form, like the appearance of a cumulus cloud.
"the triggers and conditions you mentioned were not abundantly in evidence": It is not possible to "see" any of the triggers either. But all of these can be detected and quantified by taking observations (especially of the wind) over a reporting network at the same time (both surface and upper air) and then analysing them on a map in some way - manually or by using a computer model.
"puzzling !" Maybe it is, but reasons for all of it, in terms of what I have outlined here, can be found if there is sufficient information and knowledge about the environment and the atmosphere at the time.
Joined: 15 May 2007
Posts: 969
Location: north-east victoria
Posted: Fri Jan 18, 2008 11:54 pm Post Subject:
AHA! thank you Hector, i think the windshear factor makes heaps of sense, regarding the generation of a venturi effect
not so sure that the convergence of air masses must only go up.........i'm used to thinking that the low pressure zone produces cyclones and tornadoes with a spiral lifting dynamic..........might logically conclude that convergence and resultant high pressure produce the stable, dense , clear air that we normally associate with high pressure systems
all the links that you gave me say the opposite of what you said, that convergence can and will produce higher pressure
y-e-e-s-s, we'll get back to gravity waves tomorrow, if you're game...........passing the buck from gravity to air looks like a long bow to draw !!!!!!!!!!!!!!!!! i'll have to google around moutain waves also........spent a little time on the mountain, never saw a mountain wave, must be an academic phenomenon
your question about the forecast, i can't answer categorically.....there was a forecast for possible thunderstorms, with a high base level, low moisture and high risk of fire resulting from lightning strikes, which all came true, but no specific forecast for pre-dawn storms, that i heard
now, my question about the meaning of "synoptically" , in the context of your post, you did not answer...........i'll be bitterly disappointed if i'm forced to conclude that you're trying to blind me with science........
my main question , about the relationship of electrical forces to air movement, you did not answer directly, but seemed to infer that because the formation of ice and the incidence of lightning is known to be connected , but the connection is not understood, then the role of potent electrical forces in the atmosphere can be ignored, simply because it cannot be explained ??
i think it is important that you should be able to confess ignorance of the total process, even if you receive a high salary , as a recognised "expert " or "authority" in the field........i think the Hindu term for this is "avadya" or something similar........it's quite "good form" for me to admit ignorance, you see, because that is what i am promoting........if one admits ignorance, there is room to learn something................................
synoptic - 1. In general, pertaining to or affording an overall view. In meteorology, this term has become somewhat specialized in referring to the use of meteorological data obtained simultaneously over a wide area for the purpose of presenting a comprehensive and nearly instantaneous picture of the state of the atmosphere. Thus, to a meteorologist, "synoptic" takes on the additional connotation of simultaneity. 2. A specific scale of atmospheric motion with a typical range of many hundreds of kilometers, including such phenomena as cyclones and tropical cyclones. Compare mesoscale.
stability - 1. The characteristic of a system if sufficiently small disturbances have only small effects, either decreasing in amplitude or oscillating periodically; it is asymptotically stable if the effect of small disturbances vanishes for long time periods. A system that is not stable is referred to as unstable, for which small disturbances may lead to large effects. Some authors also distinguish a neutral or marginally stable case, in which disturbances do not vanish, but also do not grow without bound. Classically, stability was defined only with respect to systems in equilibrium. More recently it has been extended to apply to evolving systems, for which an unstable disturbance leads to an evolution that becomes uncorrelated with the undisturbed evolution. From this standpoint stability and predictability can be equated. 2. Same as static stability. 3. The property that each computed solution (in exact arithmetic) of a finite difference approximation remains bounded for all possible choices of the time step. See Lax equivalence theorem. 4. The ability of laminar flow to become turbulent in a fluid.
convection - 1. In general, mass motions within a fluid resulting in transport and mixing of the properties of that fluid. Convection, along with conduction and radiation, is a principal means of energy transfer. Distinction is made between free convection (gravitational or buoyant convection), motion caused only by density differences within the fluid; and forced convection, motion induced by mechanical forces such as deflection by a large-scale surface irregularity, turbulent flow caused by friction at the boundary of a fluid, or motion caused by any applied pressure gradient. Free and forced convection are not necessarily exclusive processes. On a windy day with overcast sky, the heat exchange between ground and air is an example of forced convection. On a sunny day with a little wind where the ground temperature rises, both kinds of convection take place. 2. (Or gravitational or buoyant convection.) Motions that are predominantly vertical and driven by buoyancy forces arising from static instability, with locally significant deviations from hydrostatic equilibrium. Atmospheric convection is nearly always turbulent. Convection may be dry, that is, with relative humidities less than 100%, especially in the boundary layer, but is commonly moist, with visible cumuliform clouds. Most convective clouds are driven by positive buoyancy, with virtual temperature greater than the environment, but clouds with precipitation, evaporation, and/or melting can produce negatively buoyant convection. See slantwise convection. 3. As specialized in atmospheric and ocean science, a class of relatively small-scale, thermally (can be driven by salt concentration in the ocean) direct circulations that result from the action of gravity upon an unstable vertical distribution of mass. (In the case of slantwise convection, though, the motions are larger scale, and are driven by a combination of gravitational and centrifugal forces acting at an angle to the vertical.) Almost all atmospheric and oceanic convection is fully turbulent and is generally composed of a collection of convection cells, usually having widths comparable to the depth of the convecting layer. In the atmosphere, convection is the dominant vertical transport process in convective boundary layers, which are common over tropical oceans and, during sunny days, over continents. In the ocean, convection is prominent in regions of high heat loss to the atmosphere and is the main mechanism of deep water formation. Moist convection in the atmosphere is characterized by deep, saturated updrafts and downdrafts, and unsaturated downdrafts driven largely by the evaporation and melting of precipitation. This form of convection is made visible by cumulus clouds and, in the case of precipitating convection, by cumulonimbus clouds. Moist convection and radiation are the dominant modes of vertical heat transport in the Tropics. 4. In atmospheric electricity, a process of vertical charge transfer by transport of air containing a net space charge, or by motion of other media (e.g., rain) carrying net charge. Eddy diffusion of air containing a net charge gradient may also yield a convection current.
convective activity - General term for manifestations of convection in the atmosphere, alluding particularly to the development of convective clouds and resulting weather phenomena, such as showers, thunderstorms, squalls, hail, tornadoes, etc.
convective available potential energy - (Abbreviated CAPE.) The maximum energy available to an ascending parcel, according to parcel theory. On a thermodynamic diagram this is called positive area, and can be seen as the region between the lifted parcel process curve and the environmental sounding, from the parcel's level of free convection to its level of neutral buoyancy. It may be defined as CAPE = (a[&agr;]p - a[&agr;]e)dp, where a[&agr;]e is the environmental specific volume profile, a[&agr;]p is the specific volume of a parcel moving upward moist-adiabatically from the level of free convection, pf is the pressure at the level of free convection, and pn is the pressure at the level of neutral buoyancy. The value depends on whether the moist-adiabatic process is considered reversible or irreversible (conventionally irreversible) and whether the latent heat of freezing is considered (conventionally not). Compare convective inhibition.
convective cloud - A cloud that owes its vertical development, and possibly its origin, to convection.
convergence - 1. The contraction of a vector field; also, a precise measure thereof. Mathematically, convergence is negative divergence, and the latter term is used for both. (For mathematical treatment, see divergence).Compare confluence. 2. The property of a sequence or series of numbers or functions that ensures that it will approach a definite finite limit.
convergence band - Same as convergence line. Convergence bands in fair weather can form under thermal updrafts, and often form a fishnet or honeycomb pattern with the cell size of the same order as the depth of the mixed layer.
gravity wave - (Also called gravitational wave.) A wave disturbance in which buoyancy (or reduced gravity) acts as the restoring force on parcels displaced from hydrostatic equilibrium. There is a direct oscillatory conversion between potential and kinetic energy in the wave motion. Pure gravity waves are stable for fluid systems that have static stability. This static stability may be 1) concentrated in an interface or 2) continuously distributed along the axis of gravity. The following remarks apply to the two types, respectively. 1) A wave generated at an interface is similar to a surface wave, having maximum amplitude at the interface. A plane gravity wave is characteristically composed of a pair of waves, the two moving in opposite directions with equal speed relative to the fluid itself. In the case where the upper fluid has zero density, the interface is a free surface and the two gravity waves move with speeds where U is the current speed of fluid, g the acceleration of gravity, L the wavelength, and H the depth of the fluid. For deep-water waves (or Stokesian waves or short waves), H >> L and the wave speed reduces to For shallow-water waves (or Lagrangian waves or long waves), H << L, and c = U �[±] (gH)�. All waves of consequence on the ocean surface or interfaces are gravity waves, for the surface tension of the water becomes negligible at wavelengths of greater than a few centimeters (see capillary wave). 2) Heterogeneous fluids, such as the atmosphere, have static stability arising from a stratification in which the environmental lapse rate is less than the process lapse rate. The atmosphere can support short internal gravity waves and long external gravity waves. The short waves (of the order of 10 km) have been associated, for example, with lee waves and billow waves. Such waves have vertical accelerations that cannot be neglected in the vertical equation of perturbation motion. The long gravity waves, moving relative to the atmosphere with speed �[±](gH)�, where H is the height of the corresponding homogeneous atmosphere, have small vertical accelerations and are therefore consistent with the quasi-hydrostatic approximation. In neither type of gravity wave, however, is the horizontal divergence negligible. For meteorological purposes in which neither type is desired as a solution, for example, numerical forecasting, they may be eliminated by some restriction on the magnitude of the horizontal divergence. The above discussion is based upon the method of small perturbations. In certain special cases of water waves, for example, the Gerstner wave or the solitary wave, a theory of finite-amplitude disturbances exists. See shear-gravity wave.
Some of the symbols have not survived the copy/paste (or were like that in the original). I'm in a hurry - going away for 4 days. I will correct/clarify when I get back.
Joined: 15 May 2007
Posts: 969
Location: north-east victoria
Posted: Sat Jan 19, 2008 4:09 pm Post Subject:
Hector,
you have persistently ignored my main question
please own up if you don't know the answer, and if , in your opinion, and to the best of your knowledge, the body of scientists who depend on the taxes of working, productive people , also don't know
personally, as a productive worker and taxpayer, i don't mind funding pure research, into knowledge for its own sake, nor do i mind funding directed research, into avenues which may bear no fruit
i do object, however , to funding people who take a supercilious stance, and call me harsh names, such as "obtuse", when i am sincerely accepting those people, warts and all, and facilitating them into fora in which their knowledge can benefit me and others
this was the thrust of the conversation, since you were cordially invited back into the discussion........in some ways, you have responded magnificently, and for this , i and some others are grateful
it seems that you somewhat underestimate our value and intelligence, in general, which is a trap that nobody else here has fallen into , with respect to you.
please have the goodness to reread the questions put to you, and answer them to the best of your ability
you have, in my opinion, a certain obligation to the general public, to disseminate your specialist knowledge.......it is not expected that you should know all the detail of every mystery of creation, but you have been paid by virtue of the work of other people, and for this , you are in debt
so come down off your high horse, feel your dependence, and your obligation, give credit where credit is due, on this site, for the efforts of we who try to uncover the truth against some pretty weird and unwonderful resistance
I am reading with interest .... just want to post a big SUPPORT for Steve ...
I very much value your efforts and input Steve.
I have indicated my respect for Hector, as have others in some recent posts - but, sadly, I don't think it is mutual. Hector is a big fish in this little pond.
I'm at Matamata Aerodrome; the Walsh Memorial Scout Flying School helping my colleague with the weather briefings for student pilots. It turns out that there is pretty good Internet connectivity here, and pretty interesting weather as well!
In the gravity wave paragraph above, the formula is supposed to mean
c = U ± sqrt(gH)
where the U is the mean velocity of the fluid.
And ?[±](gH)? is supposed to mean ± sqrt(gH)
The main question...
steve clougher wrote:
so, what about the electrical component? once these towers of warm air are rushing upwards, and your adiabatic cold winds are howling down the guts, you get , as in this case, potent lightning . my question is, does the voltage difference come from the action of air, or does the voltage difference have something to do with setting the air in motion??
I answered
Quote:
The separation and build up of electric charge in convection is still not fully understood by the cloud physicists. They do know it has to do with the presence of ice or the freezing of water droplets, and their movement in the up/down drafts. When there is no freezing, there is no lightning.
Then
steve clougher wrote:
my main question , about the relationship of electrical forces to air movement, you did not answer directly, but seemed to infer that because the formation of ice and the incidence of lightning is known to be connected , but the connection is not understood, then the role of potent electrical forces in the atmosphere can be ignored, simply because it cannot be explained ??
Let's just go through this carefully.
"towers of warm air are rushing upwards": I'm not sure where this idea originated. Adiabatic means a process where no energy is not added to or removed from the process. In the general discussion of convection there is also the notion of pseudo-adiabatic process when there is condensation of water vapour.
"you get , as in this case, potent lightning": No, the lightning does not come from the warm air rushing up and
the cold air howling down.
"does the voltage difference come from the action of air": No, it does not.
"or does the voltage difference have something to do with setting the air in motion??": No, it does not.
I gave a partial answer to the question of where the potential difference comes from, and by that implied that is does not come from some other process.
It's not a matter of owning up to ignorance. If some process is "not well understood by the cloud physicists" (and therefore, every body else) I suppose you could harshly say we are all ignorant of it. And it's not a question of it being ignored or not. The situation is that it plays no part in generating the air currents.
It is the buoyancy, originating from the latent heat of condensation being released to heat the rising air (or more precisely, prevent it from cooling as fast as it would if there were no condensation) that generates the updraught. The entrainment of air with falling ice/hail/rain and evaporative cooling (latent heat again, and negative buoyancy this time) that drives in downdrafts. I've just re-read the top of this topic; the initial question and answer. The original question (it seemed to me) was about the origin of the convection; the triggering mechanism at the unusual time of day for vigorous convection and thunderstorms. The origin and effect of the electricity was a supplementary question. If in fact that was actually the original question, then it was far from clear.
To clarify the other matter: There is no absolutely no obligation for me to post here; no matter where I might work or what I might know or what skills I might have. I do not post here on behalf of any one or anything, and I'm not funded to post here. I choose to post here of my own volition. Anything I do post is solely my opinion, and not necessarily that of anyone else's. My posts here are no more or less important than anyone else's and I harbour no disrespect for any one who posts or reads here. If I did, why would I bother posting?
What I object to is people reading far more than is reasonable into what I post as an explanation of something, especially if it is in response to a reasonable question. The objection is amplified if there is thinly veiled antagonism and accusations that I may be trying to hood-wink the audience. I apologise to steve if, in a private message, I caused offence.
I endeavour to compose my posts to be clear in meaning and free of ambiguity so that nothing more than was intended can be inadvertently construed. The veracity of anything I post can easily be checked elsewhere on the Internet or in other resources in the public domain. I don't think I need to give references for every statement I make! I have not held my self out to be an expert or authority on anything.
On the other hand, anyone who says anything dodgy or daft deserves to be called on it.
Joined: 15 May 2007
Posts: 969
Location: north-east victoria
Posted: Mon Jan 21, 2008 9:58 pm Post Subject:
ok, Hector, i accept your apology, your private message was a bit stiff
as for going through the thing carefully, have another look at that sentence, following
the questions i have raised, about gravity waves, which seem to have a totally ad hoc meaning, about convergence of air masses being able to induce pressure and heat increasers, which, in fact , would give an easy "out" as regards the mystery of early morning violent electrical storms, the question of the relationship of lightning to air movement, these have been sideswiped , in a dismissive manner, with blanket denials that the questions were ever valid in the first place
c = U ± sqrt(gH)..........what is this ??? how does it relate to this :
"I endeavour to compose my posts to be clear in meaning and free of ambiguity "
it seems more like that you have posted large and expansive posts, with more of an intention to claiming innocence from blame for exactly what you
actually do, than to elucidating the issues under consideration
try being friendly, and listening to what people are saying.........what you refer to as "dodgy or daft" frequently has more to it than you are willing to accord, with your failed attempt to "not hold yourself out to be an expert or authority on anything"..(sic)
we are happy to accord you the status of expert...........after all the taxes we have paid for your training and services, you had bloody well better be expert
just calm down, and take things at a pace that we can all manage, cut down the size of your posts a bit, resonate with the inquiring spirit, and the spirit of mystery, ............if you are being truthful about your independence, and sincere in some of the claims you make, you will find friendship here
how about an explanation, first up, about the contradiction in the statements about convergence? on one hand, convergence leads to pressure and heat, on the other, it can't allow mergeing, and must go up !
steve
those whom the gods wish to destroy, they first make proud
the questions i have raised, about gravity waves, which seem to have a totally ad hoc meaning, about convergence of air masses being able to induce pressure and heat increasers, which, in fact , would give an easy "out" as regards the mystery of early morning violent electrical storms, the question of the relationship of lightning to air movement, these have been sideswiped , in a dismissive manner, with blanket denials that the questions were ever valid in the first place
Could you please, for simplicity, perhaps in separate paragraphs, and one at a time, state what the problem is with each issue, and then put a question, each of which I will attempt to answer.
Quote:
c = U ± sqrt(gH)..........what is this ??? how does it relate to this :
"I endeavour to compose my posts to be clear in meaning and free of ambiguity "
In a hurry I posted some items from a glossary site. One of the items contained a mangled formula. Later, as I said I would, I posted the de-mangled formula. The context for it, obviously, is the earlier post. That's how it relates.
Quote:
...what you refer to as "dodgy or daft" frequently has more to it than you are willing to accord, with your failed attempt to "not hold yourself out to be an expert or authority on anything"..(sic)
Please give an example where I referred to a particular post as "dodgy or daft". And what more is there to it than I was willing to accord?
Incidentally,
http://en.wikipedia.org/wiki/Sic! wrote:
Sic is a Latin word, originally sicut meaning "thus", "so", or "just as that". In writing, it is placed within square brackets and usually italicized — [sic] — to indicate that an incorrect or unusual spelling, phrase, punctuation, and/or other preceding quoted material has been reproduced verbatim from the quoted original and is not a transcription error.
So where is the spelling mistake or grammatical error?
Quote:
how about an explanation, first up, about the contradiction in the statements about convergence? on one hand, convergence leads to pressure and heat, on the other, it can't allow mergeing, and must go up !
Please quote what you see as the contradictory statements, and where they appear (post or web site).
Deano, my name is Ross; Rosco is a completely different person. And, no, I'm not going to post my CV. My profile says that I am a meteorologist working for MetService. Actually, I joined New Zealand Meteorological Service (as it was then) in February 1977, and I have been employed there as a meteorologist since then.
