Because the low latitudes of the Earth, the areas near the equator, receive more heat9 ?2 y1 ]7 P; `
Than the latitudes near the poles, and because the nature of heat is to expand and move,
6 T/ F- C6 G) C9 r0 ?Heat is transported from the tropics to the middle and high latitudes. Some of this heat is - ?% f/ l6 a& b9 Z' r' I
Line Moved by winds and some by ocean currents, and some gets stored in the atmosphere in
% h u: |8 G2 }7 b9 T(5) the form of latent heat. The term “latent heat” refers to the energy that has to be used to
$ b) X( \" Y. c& V2 ]# @5 G6 fConvert liquid water to water vapor. We know that if we warm a pan of water on a stove,8 o- D9 j; N0 V& \* y, o/ X: K- b
it will evaporate, or turn into vapor, faster than if it is allowed to sit at room temperature.
5 w' u1 I" W9 ?( L& D# wWe also know that if we hang wet clothes outside in the summertime they will dry faster ; b! \/ @4 b6 F! s
than in winter, when temperatures are colder. The energy used in both cases to change
. @3 j: z0 E& f3 z% P(10) liquid water to water vapor is supplied by heat—supplied by the stove in the first case, c5 `5 N6 k7 t& {# N5 I8 S) d
and by the Sun in the latter case. This energy is not lost. It is stored in water vapor in the 5 k8 D- S+ R, [4 B+ A
atmosphere as latent heat. Eventually, the water stored as vapor in the atmosphere will7 A2 u! E8 }! `; e
condense to liquid again, and the energy will be released to the atmosphere.
$ a. y4 O( k9 e" p- ~ In the atmosphere, a large portion of the Sun’s incoming energy is used to evaporate + C9 e! o6 }1 a# x
(15) Water, primarily in the tropical oceans. Scientists have tried to quantify this proportion 7 K F, Z @" @4 L' c, b; N' Q: R
of the Sun’s energy. By analyzing temperature, water vapor, and wind data around the
2 e$ O' j j' _5 Q' i- C2 Fglobe, they have estimated the quantity to be about 90 watts per square meter, or nearly 4 e5 O! \! P5 M# Y& z3 Z$ B# j
30 percent of the Sun’s energy. Once this latent heat is stored within the atmosphere, it 4 a7 \& a- i: T
can be transported, primarily to higher latitudes, by prevailing, large-scale winds. Or it 0 a, u$ _6 X9 J/ R0 U5 V/ x8 n
(20) can be transported vertically to higher levels in the atmosphere, where it forms clouds& Z8 B0 \8 X( {8 N& o) ]
and subsequent storms, which then release the energy back to the atmosphere.
# |6 G0 B$ {7 {' H( i8 C31. The passage mainly discusses how heat
( ~) Z' Y% ?2 K4 m# d, Yis transformed and transported in the Earth’s atmosphere5 |: D8 D, H+ R" \
is transported by ocean currents
+ W3 A) m, `3 v- e# `can be measured and analyzed by scientists: j/ C% x- V3 _( e2 @) F( D: n
moves about the Earth’s equator- @ m: H$ C6 F) X
32. The passage mentions that the tropics differ from the Earth’s polar regions in which of the following ways?
4 Y; q' u2 E( g, NThe height of cloud formation in the atmosphere$ ~; \3 H4 X- d1 H& R
The amount of heat they receive from the Sun
# E+ |0 i' ]- U! R* [The strength of their largescale winds.
( u0 x2 S8 @/ K, D7 j8 yThe strength of their oceanic currents
) i( q/ z! l* u T0 X33. The word “convert” line 6 is closest in meaning to
" ^# o$ c/ [! _2 Z. Q, z; W. Imix$ N% c1 t1 F& u& `" U! f
change
& j2 p7 f. E( w( }% [. k' K- Y) @adapt# v% W R2 e% F5 M% B# ]
reduce
9 o W- m3 ]8 h, V% c0 q
! F' \$ Z! z6 o! V34. Why does the author mention “the stove” in line 10?4 } D/ V6 f0 i. s4 D0 P9 m
To describe the heat of the Sun4 R# K7 l/ G. n W& B, D
To illustrate how water vapor is stored
) ^4 h+ L; ?) V1 Q" CTo show how energy is stored
, Y1 \# [6 s3 q s" B3 U. JTo give an example of a heat source |