The water balance~! by zhang binghui

Hi, everyone! This is Binghui. Today it's my turn to write the blog.

Basically, what we learned today is The Water Balance.

Here is a picture of hydrologic cycle for your better understanding:


The water balance is a simple equation which describes how precipitation may be accounted for within a drainage basin.

A general water balance equation is:
P = Q + E + ΔSwhere
P is total precipitation
Q is total streamflow (runoff)
E is evapotranspiration
ΔS is the change in storage (in soil or the bedrock)

Some examples of the factors:
Q can be affected by dams, but the teacher said not very sure about it.
E can be affected by vegetation
ΔS can be affected by amount of soil and also type of soil.
The water balance is used by hydrologists to plan and manage water supply within a drainage basin. It can be used to suggest possible water shortages for which special measures like hosepipe bans can be implemented to preserve stocks. It has implications too for irrigation, pollution control and flooding. The water balance can be illustrated using a water balance graph which plots levels of precipitation and evapotranspiration often on a monthly scale.
There are some additional points:

1. Precipitation in the form of rain, snow, sleet, hail, etc. makes up the primarily supply of water to the surface. In some very dry locations, water can be supplied by dew and fog.

2. Evaporation is the phase change from a liquid to a gas releasing water from a wet surface into the air above. Similarly, transpiration is represents a phase change when water is released into the air by plants. Evapotranspiration is the combined transfer of water into the air by evaporation and transpiration.

3. Soil moisture storage refers to the amount of water held in the soil at any particular time. The amount of water in the soil depend soil properties like soil texture and organic matter content. The maximum amount of water the soil can hold is called the field capacity. Fine grain soils have larger field capacities than coarse grain (sandy) soils. Thus, more water is available for actual evapotranspiration from fine soils than coarse soils. The upper limit of soil moisture storage is the field capacity; the lower limit is 0 when the soil has dried out.

4. The change in soil moisture storage is the amount of water that is being added to or removed from what is stored. The change in soil moisture storage falls between 0 and the field capacity.

Take note of this, ΔS can be zero. There are some reasons we discussed in class:
1. It can be raining all the time caused the soil saturated, thus ΔS become zero.
2. It can also be no rain at all caused ΔS to be zero.

Lastly, I am not very sure about the question the teacher asked us in class:
Can S be reduced? The answer is yes.
But what is the reason? Can someone who understood this tell me the answer?

I think the lesson is too short, only half an hour.
These are all what we learned.
Thank you!

Binghui
31, 01, 2009

geogpost-o-matic by Matthewlimtianwang

Hey All! This is Matthew And I'll be blogging what we learnt last lesson.
First off, we started talking about water from the hand out that we received.
We deduced that water.
-Has a high specific heat capacity.
>Its able to absorb more heat without turning into gas.
>Very big range in between states, solid, and gas.
-Many many things have water in it.
>Us!
>Plants
>Many things need water to manufacture.
-Drinkable
-Hydrogen bonds
>DNA
>Ice floats
-Ice
>Insulator, it protects the water that is not exposed to the air.
-Universal solvent
-The Earth is mostly water, but we cannot use ocean water as.
ITS TOO SALTY BABY!

okay, time to go on to the next part of the lesson.
the...
HYDROLOGICAL CYCLE
and unusually the caption is,
"what goes around comes around"

Made up of many parts,
Infiltration
Overland flows
etc..

I will scan in the entire picture next week when i get my scanner fixed.
Some terms that we've learnt that day was:
Infiltration Capacity - Rate at which water soaks into the soil.
>affected by:
->Saturation of water.
->Compaction, type of soil.
->Surface area exposed to the water.
->Porous, permeability of the soil.
->If the soil is frozen or not
->Vegetation

Water table - Demarcates the saturated and unsaturated zone, its not the same throughout the year.

Methods of input: Precipitation
Methods of output: Evotranspiration, which is a combination of transpiration and evaporation.

Storages - Groundwater, soil moisture.

Flows - Infiltration, overland flow.

Flows can also be in different categorieroots take in water
Inbetween surface and groundwater - Through flows.
Groundwater - Base flow
Vertically in the soil - Percolation

Interception - Anything that hinders movement of water from precipitation
> Vegetation - reduces impact of rain drops, reduces rain splash erosion.
->stuck in leaves
->roots take in water
->stemflow
->Throughfall






THATS ALL FOLKS!
bwahha.
Matt!

My apologies everyone, I saved it in my comp and forgot to post. So it’s a little back-dated somewhat. I’ve made changes and the last part of reflection was something I added in recently. Yup, so here goes.

Hello.

I’m going to briefly run through today’s lesson and then do some reflecting.

Goodbye Peixin, Hello Ms Tang.

It was Ms Tang’s first lesson with us.
Some interesting notes:
1.

Good attitude
Engagement
Ownership
Grow!!

2.

Desert is spelt as desert, if you forget and spell it like dessert, do look at the picture below.

3.

Some people have funky-looking camels


Point 1
Wind moves from HIGH pressure to LOW pressure

Point 2
Cold air --> high pressure
Hot air --> low pressure

Point 3
Air rises --> rain

RECAP
The Hadley and the Polar cell are driven by the SUN.
The Ferrel cell is induced by the Polar and the Hadley cells.

The desert belt occurs where the air subsides.
Air subsides (where the arrows go down)
--> no uplift of air (i.e. air does not rise)
--> no rain
--> deserts

REFLECTION
I was whacked during lesson and it was hot and noisy.
I learnt that concept maps are useful for firstly identifying key concepts and secondly it helps us see the links between ideas and concepts.
Eh, I haven’t got much to reflect on the one and a half hours.
We kind of just revised some concepts, got to know ourselves better, and did a concept map on what we have learnt thus far in this module.

---

As I sit through, not just this lesson but all our lessons, I just kind of keep thinking that the world we live in is so huge, so awesome, so wild.
Yet here we are, tiny and insignificant yet trying to contain this gloriousness into words and diagrams.
Trying to manipulate, predict, exploit great things we can neither understand nor control.
We see a little and we make much of it.
We feel a little and we assume much from it.
We think a little and we decide we can re-create it.
Who are we?

Makes one think huh. Exams almost seem frivolous compared to this.
Ever sat back, looked at those hand-drawn air-cell diagrams and think, and silently ask in the general direction of the teacher, have you seen the earth as a ball? Have you experienced the force of tornado? Have you even tasted the brutality of the desert? Have you seen wind move in ways beyond all humans can imagine?
Sometimes I look at geography, and augh, how shall I say this.
Like,
WAKE UP, HELLO, YOU’RE TALKING ABOUT THE EARTH LIKE IT’S A BALL,
OF THE GALAXIES LIKE IT’S YOUR BACKYARD.
Wake up, ever thought of how small and puny our efforts are to record all these?
Yet we do it, why? I honestly don’t know.

Hahahahah, I sound like I’m ranting but I’m quite serious.
We, as students, sit in class, learning about things of such complexity and beauty, yet all we care about is, oh crap this module is gonna kill my GPA, or aiya only 3 credits.

I’m just suddenly appalled that we are trying to squeeze something great and make it small, boring and “muggerable” (which means able to mug for).
Sigh.

I think as we drill down deep, we find that there are things we just do not have answers for.
Yet we keep asking. :D
Humans ARE complex huh but also beautiful, like the rest of the earth.
So in conclusion,
As we learn all this, doesn’t even need to be geography, can be science or even LA,
I guess it’s important that we take a step back, and look at things from a different perspective eh?
One where grades are not everything, one where the classroom is not the ends of the world, and one where you know, we can really just stare in awe of the glorious wonder of all creation.

The end.

Esther.
PS: and I thought I had nothing to say.

IS 2104 lesson on 5th march 2009

It was our last IS2104 lesson for the term. Naturally, everyone was sad about it. Worst still, it was only our new physical geog teacher second lesson with us, which is such a pity since she's so nice.


This is her!

That day was hot and humid, but because of that wonderful lesson that we had, the day seemed less painful to get through. Our new geog teacher, (who's name i forgot, sorry), was charming and nice.

Anyway, back to the lesson. That final lesson for the term was spent on going through wind patterns. We talked about how winds are formulated on earth. The following picture simply put together what i want to tell you all.



yup, so basically that sums up everything about wind patterns. Remember the directions the wind in each section blows in. They are really important. Also, you must remember the all the names given the each wind pattern in each section of the Earth. I must admit, the names are really weird. And cute, but this makes it easier to remember. :)

After that, our new geog teacher evaluated the mind map that everyone did last week. There were some that were great, but there were some that were not that good. I'll state down which is the best, and you can use that for revision.


This part is great. Because the hardley cell and polar cell had a connection with the ferrel cell. Yes people, there is indeed such a connection, so remember.


Ok, this is quite a bad mind map. The basic ideas are there, but details aren't being made. If it was elaborated on much more, it would have been better.


This one is the best based on our new geography teacher. This is because the carbon cycle is shown without really stating it. ( notice the crooked lines there if you don't know where to find it). But of cause its not totally perfect. There are details missing here and there, but its alright.

For the best result, it is suggested that you make your own mind map, while using the good points from each of the three mind maps ive shown you.

This is as everyone knows, the weekend before ass week. When you do not feel like studying, like how i'm feeling right now, but go and sleep. It works. And don't feel all guilty about slacking a while from time to time. Because all work and no play makes jack a dull boy. :)

Alright ending off here. Jia you everybody! jeremy




smile and don't strees :)

Tilt and Shape: Season 2 (27th Feb)

Hello.
Sorry for the delay in posting. It's basically the same as mak's, but probably not so defined and content-based. Because i wasn't in school for that lesson, and the rest of the class wasn't sure about it anyway. Hence, we revised everything again for this lesson. By the way, could someone help me explain how autumn and spring come about and how are they different? Sorry, I didn't get it and it wasn't really explained in class that day. Thanks!

Why are there seasons?



Seasons occur due to the Earth’s tilt.
Note: Radiation from the sun does not weaken with distance. It only gets cooler when the distance between you and the sun is larger as the radiation is spread over a bigger area and is thus less intense. So, when explaining about the sun’s rays, cannot write hotter/colder.

1. As the Earth is so huge, a small tilt in the Earth’s axis will result in a change of distance between the Sun and each hemisphere. Hence, when the northern hemisphere is inclined towards the sun, meaning it is nearer the sun, the Sun’s rays are/solar radiation is more intense on the northern hemisphere, hence it experiences summer. They/it are/is less intense on the southern hemisphere, as it is further away from the sun, thus it undergoes winter.

3. The southern hemisphere is inclined towards the sun, meaning it is nearer the sun, so the Sun’s rays are/solar radiation is more intense on the southern hemisphere, hence it experiences summer. They/it are/is less intense on the northern hemisphere as it is further away from the sun, thus it undergoes winter.


Explain the distribution of Earth’s Climate.



Basically everything is explained in the diagram. Hence, the content seems very little, haha. Anyway, pardon my messy handwriting(:

I feel that this lesson was quite informative, as I've never known that the world's climate was brought about by the movement of air within the atmosphere. I've not looked at it as a whole system before, only from certain segments, like the water cycle. Therefore, this lesson enabled me to appreciate the big picture and how it all works out. Also, it's interesting to know that deserts are not found at the hottest area on Earth,the equator, where one would naturally expect deserts to be at. That's one point to note. Another thing, I knew that seasons were caused by the tilt of the Earth, however I did not really know how they were actually brought about. Hence, this lesson provided alot of details and explanations that added to my existing knowledge and allowed me to understand the topic more thoroughly.
The End.

- Jia Yi