LAND AND SEA BREEZE

Formation of Sea breeze

Diagram (2m)

-        Land : Higher temperature, Lower pressure

-        Sea : Lower temperature, Higher pressure

-        Direction of sea breeze

-        Warm air expands and rises, cool air sinks

Explanation (2m)

-        During the day, the land heats up faster than the sea.

-        Air over the land surfaces heats up as it expands and rises, whereas air over the sea cools and sinks.

-        Therefore, it creates higher pressure over the sea, and lower pressure over the land.

-        As a result, wind blows from the sea to the land during the day to form a sea breeze.

Formation of Land breeze

Diagram (2m)

-        Land : Lower temperature, Higher pressure

-        Sea : Higher temperature, Lower pressure

-        Direction of land breeze

-        Warm air expands and rises, cool air sinks

Explanation (2m)

-        During the night, the land loses heat faster than the sea.

-        Air over the sea heats up as it expands and rises, whereas air over the land cools and sinks.

-        Therefore, it creates higher pressure over the land, and lower pressure over the sea.

-        As a result, wind blows from the land to the sea during the night to form a land breeze.

 

 

  

Maritime and continental effect

Maritime Effect:

Effect large ocean bodies have on climate of coastal areas.

•Small temperature range

•Cool summers and warm winters

Continental Effect:

Effect huge land surfaces have on climate of inland areas.

•Large temperature range

•Hot summers and cold winters

class test - temperature answers

1	(a)	City Latitude Altitude Mean annual temperature Santiago (Chile) 33°27′S 520 metres 18°C Sydney (Australia) 33°52′S 110 metres 32°C
		Table 1
		With reference to Table 1, explain why Santiago and Sydney experiences different temperatures.                                                                                                                   [4] -        While both places are located at a similar latitude, Santiago is located at higher altitude of 520m as compared with Sydney which is located at lower altitude of 110m. -        At lower altitude, there is more long wave radiation as heat is absorbed by the earth near the ground surface, which results in higher temperatures. -        Whereas at higher altitude, there is lesser longwave radiation as the air is less dense, resulting in lower temperatures. -        This accounts for Chile experiencing a lower mean annual temperature which is 14°C less than Sydney. Remarks : Most students didnt explain about longwave radiation. Some mention that it is due to distance from the sea (But the question did not provide any evidence to sea, so DO NOT blindly memorize and regurgitate from the text book!). Also need to provide data from the Table 1 eg 520m in altitude. Some students do not understand what 'Altitude' means and think that is the distance to the sea. Altitude means height of a place!
	(b)	State the difference between the terms “Weather” and “Climate”.                                 [2]                             -        Weather refers to the atmospheric condition of a place at a specific time. -        Climate refer to the atmospheric condition of a place over a long period of time, usually over 30 years.   Remarks : A few did not wrote '30 years'. Weather is NOT only about TEMPERATURE.  Perfect ans: Armin, Chikin
	(c)	(i) What does the instrument in Fig. 1 measures?  What does the instrument in Fig. 1 measure if it is placed in the field for a duration of 24 hours?                                           [1]                                                                                                                                                                    Maximum and Minimum Temperature  Remarks: Some wrote sling psychrometer/Relative humidity! Its not the same!
		(ii) State 3 factors that may cause inaccurate data to be collected from the instrument. [3] -        Parallax error while reading off the thermometer -        Placement of thermometer under direct sunlight/ too near to the ground may cause heat radiated from the ground that will affect the reading -        The instrument may be left in the field for a long period of time which cause results recorded to be in accurate - The instrument may have been faulty and thus affect the readings. Remarks : Some students confuse the thermometer with the sling psychrometer and thus provided answers such as 'holding it too close to the body', 'swinging it at inconsistent speed' Accept any other possible answers.
	(d)	Months Temperature January 28.9 °C February 29.3°C March 29.5°C April 31.7°C May 29.9°C June 31.5°C July 32.0°C August 32.5°C September 32.9°C October 33.6°C November 32.0°C December 30.5°C Fig. 2
		(i) Calculate the mean temperature of Country X.                                                           [1]     (Total) / 12 = 31.2°C
		(ii) Calculate the temperature range of Country X.                                                         [1]       33.6°C – 28.9°C = 4.7°C Remarks : Many did not show anwers for (ii) after the calcuation. wrong units will minus half a mark.
	(e)	Describe and explain the characteristics of the Stevenson screen.                                 [3]                                                                                                                   -        White/wooden: Insulate against heat so that temperature is regulated -        Window panels/louvred sides : For ventilation -        1.5m away from the ground : To keep away from the ground as it absorbs heat

Relief lesson on Rain and RH worksheet

With reference to Figure 1, describe and explain the relationship between relative humidity and air temperature.                                                                                                                                                         [4]

Describe [2m]

-           As temperature increases, the relative humidity within a parcel of air reduces/As the temperature decreases, the relative humidity within a parcel of air increases.

OR there is an inverse relationship between temperature and relative humidity

-         For every 10 deg increase in temperature, relative humidity decreases by roughly 50%

Explain [2m]

-            Warm air has the ability to hold more water vapour

-           Hence as the parcel of air increases in temperature while the amount of absolute water vapour remains the same, there is an overall decrease in the relative humidity/percentage of air saturated by water vapour 

Identify the instrument used to obtain the readings for rainfall in Table 1 and explain where the instrument should be placed in order to get accurate measurements of the daily rainfall.                                                                                                                                                                                       [3]

Instrument = rain gauge (ignore spelling error of ‘guage’) Open grassy area / open field to reduce evaporation as it is cooler in the ground than on a concrete surface. Away from buildings and trees to prevent raindrops from buildings and trees from dripping into the rain gauge or fallen leaves and twigs from choking the funnel [3@1 mark] With reference to Fig. 1, identify the instrument used by the students and state the relative humidity recorded for that day.  Explain how the students obtain this information, using evidence from Fig.1.                                                                                                                                                                           [5]               ·        Instrument used:  wet and dry bulb thermometer (compulsory) ·        Relative humidity recorded: 61% (compulsory) ·        Read/record the dry bulb temperature, which is 33° C ·        Read/record the wet bulb temperature, which is 27° C ·        Find the wet bulb depression is 6° C  [5 @ 1 mark] One student thought that the relative humidity could be related to the depression of wet bulb. State how this relationship could be expressed. [1]                                                                                                    ·        1 mark for ‘the greater the depression of wet bulb, the lower the relative humidity’ or equivalent