Jupiter One’s self-titled album was an unexpected surprise. Full of pop gems yet stylistically diverse, it was one of 2008’s stronger debuts. Except that it was actually a reissue; the band originally self-released the album all the way back in 2005. So it’s not a shock that the follow-up, Sunshower, is hitting shelves a short 12 months later. Sunshower shows that the band continues to have a knack for a catchy melody, but it’s a knack they don’t employ on every song, to their detriment.

The album opens with “Volcano”, a great big chunk of silly power-pop. Swirling synths and tight, harmonized, “Ahhs” in the introduction give way to understated guitar and lead singer K Ishibashi’s vocals. Lyrically, the song is a narrative that involves super powers, a volcanic eruption, a girlfriend, and the girlfriend’s angry father. A father who is more interested in telling the protagonist why he’s not good enough for his daughter than in heeding the protagonist’s warning to “Get out / Get out / Get out of the house”. “Volcano” is one of those songs that gets stuck in your head instantly and has you singing along by the end of your first listen. The second track, “Lights Go Out”, is a bit harder-rocking, with lyrics about a man who can’t get over seeing his ex-girlfriend with a new guy. Ishibashi shout-singing in the refrain gives the song a bit of an edge and contrasts nicely to the opener.

Third track “Flaming Arrow” features some very nice twisted lyrics about a man getting revenge on his ex by setting her apartment building on fire. Maybe primary songwriter and guitarist Zac Colwell had some relationship issues to work out while working on these songs. It starts well enough, with a laid-back, acoustic guitar and organ-driven feel. But about a minute in, the song bursts into a huge, schmaltzy slice of ‘70’s-style AM pop, complete with unnecessary strings and lighter-than-air clean electric guitar. This shift is disarming and annoying and it pretty much sabotages the song. The next song, “Made in a Day”, is perfectly pleasant, but almost completely forgettable. But just as you think that Jupiter One is losing their focus, though, out comes “Anna.” This is the album’s other highlight, a song that mines the ‘70s much more successfully than “Flaming Arrow”. It features a huge chorus with harmony vocals and great use of a ‘70s-style distorted guitar tone, with subtle keyboard washes in the background.

But then the album really does lose its focus. The second half of the disc features a weak, disco-beat ballad in “Simple Stones”, a limp slow-dance song without any hooks (“Strange Teacher”), and a boring tune that completely wastes the great title “High Plains Drifter Finds the Oracle at Delphi”. All is not lost, though, as Sunshower does manage a few more gems. “Find Me a Place” is a gentle song by Ishibashi that has strong melodies in its verses and chorus. Ishibashi also writes the album’s closer, “People in the Mountain, People in the Ocean”, a simple, spare track that is mostly just vocals and acoustic guitar which highlights his strong falsetto. The only rocker on side two, as it were, “Come On”, also works very well. While not quite up to the level of “Volcano” or “Anna”, it has another strong chorus that marries a catchy melody to a strong backbeat.

It’s too bad that Jupiter One can’t seem to come up with a great melody every time out, because when they do the songs really pop. And when they don’t, well, they just sound flat. The band’s first album had some of these same issues, but it was so ridiculously front-loaded with good songs that is wasn’t as noticeable. That album also traded heavily in sounds from early ‘80s new wave. Sunshower trades the ‘80s for the ‘70s, but the results are similar. If there’s a strong hook, the song works, but if there isn’t one, the band isn’t musically interesting enough to make up for it. Still, when Jupiter One are good, they’re very, very good. There’s enough high quality material here to make the album worth a listen. And at a brisk 38 minutes, Sunshower doesn’t last long enough to wear out its welcome.

• Multiple songs MySpace